Hello beefstu123
according to the details you have provided other xperts, it sounds like as (nobus) said you probably have swapped some new bad parts...
As for changing the Hard disk with a brand new one, this should mean that you have to forget about the Virus issue.
The only thing which you have to think about now is hardware, I believe there's some kind of in-computability between the hardware components you have installed.
* Have you tried a new CD/DVD Rom ? Did you test the Windows CD on different machines if it boots up and can enter into the XP setup program..
[[ Text referencing illegal software removed by PenguinMod, EE Moderator ]]
Hope this helps