I have a homebuilt PC running a Gigabyte motherboard w/an AMD Athlon 2500+ CPU and nVidia peripherals. I have Window XP Home Edition with all current updates running. I do not overclock or push my system beyond its standard setup. I have about 750+ MB of RAM installed. I am writing to you right now from my laptop because I currently can get the PC to function long enough to really diagnosis. Let me describe what is occuring (and I realize that I can't give you all the specific info regarding the system that you might need) and perhaps someone can tell me if these systems are indicative of a specific problem. In a complete guess, I am starting to narrow my issues to either a corrupt operating system (which has been trouble free since original load in 2003), or a failing CPU. Okay, a couple of months ago, even though I am diligent about my virus software (NAV), I discovered that I had spyware on my system. It was winfixer which basically couldn't be gotten rid of without the use of Spybot, which I got from reading these forums. Anyhow, I downloaded Spybot and it worked great. The only reason I am mentioning Spybot is because it is the only software change I have recently made short of updates to Windows and virus software. I set the Spybot and NAV to run in the background for continous checking. Other than that, I am pretty careful to have all unnecessary services or programs running in the background. The average amount of RAM being used in Idle mode (with task manager up) is about 250 MB so I have plenty of unused RAM. I generally have a screen saver running on my system (just a standard windows one...nothing fancy). Over the last few days, I have noticed that the screen saver would lock up. I could move the mouse and after a few seconds, it would come back fine and I could continue to use my computer with no problems. Yesterday, I noticed that it would go to a complety black screen every once in a while. I figured that something was going on with the screen saver, so I disabled it. Problem continued, but seemed to be mostly in IE, so I decided that perhaps I just needed a reboot. I did the reboot (my system is always on), and things seemed better for a while. Later that evening, it started again, so I disabled NAV and Spybot background activities after scanning the system. Once again, things seemed better for a while. Thought I had the problem licked and then it started going to the black screen again. So I turned it off to deal with today. This morning, I booted it up, turned off all Spybot stuff and the screen saver and it seemed to be working fine until about an hour ago (5 hours of continous running but in idle most of the time as I wasn't on the computer). Now it is going to the black screen almost continuously. I opened performance in task manager to see what was going on and it seems that while not much RAM is being used, every few seconds or so, even though nothing is running but Windows, some services and taskmanager, the CPU usage peaks out....and when it does, the screen goes black. Okay, a few things about the black. It is not like a monitor problem, the monitor is not making any noises like it did when my old one died a few months ago. This is strickly a system thing, but I can't tell if it is a CPU thing or just some kind of glitch in XP that I need to address. The screen just turns black, and then I move the mouse around a bit, and it comes back. A few seconds later, even if I am not doing anything, it does it again. So I guess what I need to know if there is some place besides the device manager that I can go to in order to diagnose the CPU. I would also like to know what is considered a normal temp range for it, just in case it is overheating but is not giving me the warning buzz. I am also wondering if anyone has seen this activity as a precursor to CPU failure. I don't have an extra CPU to test. Does anyone know if I can burn disks from XP to back up data in safe mode? I might be able to get it to boot in safe mode. We have not had any storms or problems that would have fried the system and everything is tied into surge protectors. Thanks so much for speedy help you might be able to provide.