I built my computer myself, and it has been running just fine for a long time. It's a 1.7 GHz Intel Celeron running XP Pro. I'm using a Western Digital 40 GB Hard Drive which, until recently, was running in DMA Mode 4. A couple of weeks ago, I noticed that the computer started taking an exceedingly long time to shut itself down after I had told it to. Aside from that, there were no initial symptoms.
Next, when signing onto AIM, which is generally the first thing I do when I get into Windows, the log-on window would freeze temporarily, then continue through the three steps and sign me on. Aside from that, everything was running fine, even the UT2004 demo (in window and full screen, with AIM running) and the Hidden & Dangerous 2 demo.
Finally, I booted up a couple of days ago and clicked my quick launch icon for Internet Explorer and it took about 10 to 15 seconds to open the window. I found that very peculiar, so I tried to open some other applications and they were equally slow if not slower. My first thought was, "I am loaded up with ad-ware and spyware." I pulled out the big guns to no avail. Nothing. Not even any viruses. Then I tried defragmenting and fixing disk and registry errors. None of that worked. I tried closing down unnecessary processes, still thinking something was eating up my memory. Nothing still.
At this point, I started to think about the speed of my hard drive. I checked it, and it was still running in DMA mode 4. I tested the Hidden & Dangerous 2 Demo (which is fairly graphics intensive) to see if it would run smoothly, which it did once it FINALLY loaded.
I opened up msinfo32 and discovered that my DMA controller was sharing an I/O port with the PCI bus, which had lots of other I/O ports reserved as well. I have tried absolutely everything I can think of to wrestle that range of I/O ports away from my PCI bus. I have done everything from the smallest step of disabling my PCI devices to actually removing them and uninstalling the PCI bus drivers, ALL attempts ending in failure. I'm now not even sure if this is the problem, but it seems to me that it would be, and it is the only thing I can think of that would alter my performance so drastically (though I still don't know how the resource became shared and why performace degraded so gradually).
I have spent all day today trying to figure something out. The last thing I tried was to do a System Restore. I tried going back as far as early January and still the problem persists.
If anyone has any ideas on this one, PLEASE PLEASE lend me some brainpower. I can hardly use my computer, and I want to beat this damn bug. I'm just totally out of ideas.

How much space is left on the partition where you run XP?
How big is your Pagefile?
Have you cleaned up your PC lately? (Temp. internet files, Temp directory etc.)

11 GB left. I just use the whole drive, no partitions. I emptied all the temp directories as one of the first attempts to speed it back up. Didn't help. I dunno where to check the size of my Page File, but under the Performance tab of Task Manager, it says my Page File usage hovers around 175 MB. Anyway, unless the Page File changes itself, that isn't it, because I have made no major changes to the system. Something changed by itself to spark this problem.

possibly fragmentation, and yes the PF does change itself unless you have the minimum and maximum size set to the same. A good example and good guideline is to set it to 1.5x physical RAM.

Partitions are your friend. This allows you to more easily organise data and reduces fragmentation by isolating it to the partitions that change frequently. this saves time when defragging as well. There are hundreds of good reasons to partition your drive.

I mentioned that I already tried defragging the hard drive and that didn't help. I plan to try again, but I doubt it will make a difference. I hope it does.

you mentioned that "until recently" your HDD was in DMA mode 4, what is it now?

It still says it is operating in DMA mode 4. I said "until recently" because I suspected that my DMA controller wasn't being used because its resources were shared. Unfortunately, my friend told me that his PCI bus is also sharing an I/O port range with his DMA controller, so that isn't the problem. He told me I should turn off the page file, defrag, and turn it back on, in order to defragment the area of the disk used for page filing. I did so, with absolutely no results. I am now at a complete loss of ideas.

I can offer very little, but here is what I know:

1. When I get into Windows, my hard drive makes a loud "screech screech" noise that it never made before, kind of like the sound you would get if you scraped a knife blade on concrete. It is two swift grinding sounds, kinda like a head moving into and out of place or something.

2. Everything in Windows takes an unreasonable amount of time to open. A simple Notepad text file of one paragraph's length takes five seconds to open (which doesn't sound like much until you sit there and count them out). An Internet Explorer window takes up to thirty seconds to open. Shutdown is the same way, with an unreasonably lengthy wait before the computer finally shuts down.

3. My hard drive was just defragged, so fragmentation is not the problem. I recently deleted all the temporary files, including internet and history. My registry was just defragged and cleaned, and I have performed numerous scans for ad-ware, spyware, and viruses.

4. At the physical layer (for you OSI model geeks ) I checked all my connections, and they are all solid.

5. I made no major configuration changes prior to the emergence of this problem.

There you have it. That is the full rundown. I have nothing else to give. If anybody has some more bright ideas, keep them coming. I'll try anything that doesn't involve formatting.

when you checked the connections, did you unplug the ribbon and power cables and plug them back, if not, do that, make sure they are firmly connected(try a new ribbon cable if possible) I've seen a lot of drive problems that were actually just a semi-faulty cable. If you still get no results, check the drive for bad sectors, that sound you hear is a possible sign of bad sectors.

I'll try another cable, but wouldn't defrag pick up bad sectors? I also used a utility called Disk Fixer, part of Fix-It Utilities 4.0, and I ran it several times. It said I had no errors. I can use another utility to scan, though.

I tried scan disk. No errors at all. Haven't tried another cable yet.

Have you heard about the about industry's widespread use of faulty capacitors? It might be possible that your motherboard manufacturer used a batch of those capacitors. I had such a motherboard sadly and had the very same issues you mention. It might be worth checking into. Here are a few websites that go into more detail on it. They have a few pictures that might give you an idea of what it looks like.

http://www.overclockers.com/tips00140/

http://www.pcstats.com/articleview.cfm?articleID=195

Another thing that it might be is the Power Supply. That of course depends on what components are in your system and the power supply itself.

I'm afraid that it's going to be the Abit thing. My board is an Abit TH7-II. I bet it has a bunch of crappy capacitors. If it does, I will be mega pissed. I'm going to check right now.

I almost hoped to open my computer up to see a bunch of blown up capacitors, just so I could see the end of this. Unfortunately, not even that is my problem. I have yet to try another IDE cable 'cause I don't have one. I will have to borrow one. I don't know why my cable would crap out on me after a year of faultless performance. It isn't the power supply either. For one thing, I have been running my current setup for two months or more with no problems. Also, I removed my only two PCI devices (back when I thought that was the problem) and I still had the same problem. If it were that the supply was simply overloaded, that would've fixed it. Of course that doesn't test the supply itself, which could be crapping out on me as well as any other component, so I will have to test it too.

The problem lies with the HD. Try putting the HD on another IDE channel using a different IDE cable.

No, defrag doesn't tell you about bad sectors. Check the drive for errors and make sure you tick the "check for bad sectors".

BTW Windows builtin defrag is a joke.

When you disabled the pagefile and did the defragmentation, did you reboot the machine ater setting the pagefile to zero?

I used Windows defrag along with Fix-It Utilities 4.0's defrag, and I used each "error checking" utility with the same results. Yes, I did restart after setting the pagefile to zero, and I restarted after I set it back. No difference. I'm about to try a new hard drive cable, but first I'm going to switch channels with the cable I'm currently using. Don't really know what I'm going to do after that. I'm sure it is the hard drive too, specifically because of that noise, but it is peculiar that more than one disk scanning utility turned up no errors. Anyway, off to try some things.

I had a similar problem with things being incredibly slow to open. I oped up task manager and noticed that background tasks that dont use much of the cpu did, in fact they were using 99% of it. This ment things took incredibly long to open. When i deleted these specific tasks the load just got shifted onto another one. I eventually got ad aware (http://download.com.com/3120-20-0.html?qt=ad aware&tg=dl-2001) to run and it came up with a few spy and ad wares but by deleting them it never fixed the problem. Eventually i lost patience and formatted my hard drive to see if it would work. It was a costly sacrifice losing all my stuff but it turned out to be worth it. After formatting and reinstalling everything my pc runs fine again. So all i can suggest is to format. Its up to you to decide wheather its worth losing all your stuff, and its not garanteed it will work. Also, i think the fact that your hd makes crazy noises at startup might mean its pretty dun in.

Well, that's not the kind of thing I want to hear. My drive is still making that weird noise, and I'm almost certain now that it is a hard drive problem. I switched cables. I'm using an ATA-66 cable (which I didn't know), but I switched to an older cable and it didn't want to work at all, so I wasn't able to test it. It is far too old to be a reasonable test anyway.

Interesting note, though...
I got into Windows a few minutes ago and opened up internet explorer, and it opened as swift as ever... until my hard drive went *crunch, crunch.* Then it slowed down to a crawl. I don't know what the problem is, but I'm not going to format this thing.

PROBLEM SOLVED

And we never would have figured it out. Before I explain what happened, I want to thank the people who took the time to try to help me out. Oh, and to those of you who had ideas and didn't post them, screw you! Haha!

It was not the hard drive. It was not the IDE cable. My capacitors were not blowing up. My memory wasn't faulty. My power supply wasn't dying. My resources were just fine being shared.

"WHAT WAS IT?!?" they say!!!!

FIX-IT UTILITIES 4.0

I realized, "It hasn't updated since last week.. maybe I should do that." So I went in and it found a new update, which was odd, because I have it set up to alert me to new updates. I started installing it, and suddenly the window said, "Effective February 13th (last Friday), Fix-It Utilities 4.0 will no longer be updated." At first, I thought it was just some extra bad luck, just to tick me off. I went to their website just to see how much an update would cost. I went to their support page for FIU 4.0, and lo and behold, there was a big QUESTION at the top of the page, and it read: After installing the latest update for Fix-It Utilities 4.0, I experienced a major system slowdown. How can I fix this?

Yes, that's right, my friends. Fix-It Utilities 4.0's next-to-last update was completely screwing with my ENTIRE system, slowing down absolutely everything. By virtue of good luck or God's will (or both), I stumbled upon the solution. Thanks again, and from now on...

Weird problem solution,
Step 1:
Begin systematically closing ALL PROGRAMS

See ya.