Dieing Motherboard?

[DemonicDerek]

My dad about 1 year ago got a (dell) computer at an auction, and we added a DVD +/- RW drive so that way he could burn DVDs plus we added 512 Mb RAM and shortly afterwards I wiped his hard drive clean with windows and I Told it to have everything as 1 partition. However It took up all the space that the hard drive was said to have, and it also said another 8 mb was partitioned the motherboard thinks with imaginary 8 mb is another operating system and so we lived with the computer taking twice as long to boot but now recently my dad's computer has been extremely sluggish (it took the computer around 5 minutes to open windows explorer after booting up) and also now whenever he boots it up it says keyboard failure and I am not sure (thinking not) that he got his virus protection program up and running yet. Could there be a virus, or could the motherboard be dieing?

Things to note:

No seperate video card (he uses motherboard integrated video)

No seprate sound card (he uses motherboard integrated audio)
768 mb of RAM

1 PATA hard drive (unsure of size because he has a password on his computer)

I think it has a 2.0 GHZ or less processor from intel-NOT 100% SURE ABOUT THIS

Mouse wasn't working when I plugged it into the 6 different USB ports and kept trying about 30 times then on the 33rdish or so try it worked.

Windows XP operating system

We have no Idea how old the computer is.

[DemonicDerek]

Throughout the entire day I was doing everything I could to find out what exactly was the problem and well now I can't even start up the computer correctly! So my dad is having me make a computer componet list of what he he would need and compare it to dell and then make his decision on whether or not I get to build his new computer or he orders one from dell.

[Rob]

The computer should not be that slow. If all of the hard drive space if used then I would say that is the problem. As a general rule, the hard drive should be kept at least 20% free to prevent it from becoming a performance problem.

But I don't know about the keyboard failure. It's possible that a virus could be at least part of the problem.

[DemonicDerek]

It doesn't matter anyways I can't start up the computer normally now anyways.

He is letting me build him a new one! Yay!