i was wondering how long it would take to build it

also i was wondering how do i know what type of case to get for the mobo, and can i use the original hard drive/dvd/cd rom from my computer right now, also what about usb ports and all of that, arent usb ports integrated into the mobo itself??

while im building my computer, what type of firewiring should i get, are there any "high" performance ones,

what should i look out for

A little more info about what you are going to use the computer for would be useful. Also more info about your current drives (HDD, CDROM, etc). Most new computers will accept older drives, assuming they are standard IDE, and not really really old. Anyways, the first part of building a computer is finding out what you want to do with it and figuring out what computer parts will necessitate that. Then finding out how much you can spend.

"Most" cases today are built to handle any motherboard out there. First find out what the style of mobo you will be buying and then you will know what case to find.

Most likely, depending on how old, what style, and what mobo you get.

Depends on the motherboard, but all of them today have 2-6 ports and usually some expansion options for more. You can also purchase USB hubs that will provide additional ports from one USB port.

Are you planning on doing digital video? Firewire is typically used for external devices that need to tranfer large amounts of data. Most people use USB 2.0 which is pretty much standard on newer motherboards.



Provide more info, and we can provide better information.

Bug

okay here is what i plan to transfer onto the newe mobo

compaq cd-rom (3 yrs old)
compaq dvd player (3 yrs old)
compaq 50gb hard drive (3 yrs old)
Ati radeon 9600xt 8x agp
sound board 5.1 doubly live
2x kingston pc2700 ddr 256mb ram
amd xp 2400+ processor
compaq floppy drive(3 yrs old)

and thats all i can think of now

could i use the original case, or would i have to buy a new one

You should be fine with all of the above components. The only thing to really be aware of is that you will want to verify you do not buy an AMD 64 board as your processor will not fit. I recommend an nForce2 board, perhaps from Shuttle, Asus, MSI...

The case must be an ATX format.
http://www.obengware.com/telaah/2004/gigabytega-8trs300m5h.jpg
is one style of ATX

If the back of your case is not the same, you may be able to mod it, but you can get an ATX case for as little as $30.

Bug

Link to a mobo......

Here's a mobo that worked great for me! User friendly and no problems with it. It also got great reviews from Tom's Hardware. There seems to be a platinum which wasn't out when I got mine. I just used the MSI K7N2-Delta L. I think it will have everything you need. Has extra ports for USB and some built in. check it out
http://www.newegg.com/app/ViewProduct.asp?submit=property&DEPA=0
It's ATX Form Factor as long as your case can hold "ATX" and it's not like Mini ATX or w/e it should fit

http://www.newegg.com
and search for K7N2

Price is about 60-99 USD (Ultra 400 - Platinum) currently.
Bug

I agree, i switched from P4 to AMD i.e. MSI 845E-Max 2.4Ghz to MSI K7N2 Delta-L XP-2800,,all things used with the P4 worked Flawless with the Athlon.
BTW The K7N2-Delta needs a "Mid-Tower" or "Full-Tower" case.

No, it takes 10-15 minutes for someone very experienced to do that.

I'd say if you have never done that before, and you will be getting a new case, etc - the whole thing, then you will want to set aside a whole day / afternoon to do that.

I certainly still set aside a whole couple of hours at least to build a machine and I was a computer technician for a long time.