Trojan.Vundo - computer help forum

first of all...it's good to be here!! Hopefully someone can help me out.

I originally posted this in the windows forum but I'm also posting it here hoping that someone can help.

Ok. This is a computer I built over five years ago and was still going strong until I gave it to my son. It's got an AMD Athlon 3500+ on it. 2 Nvidia 6800 GTX in SLI and 2gigs of ram and running Windows XP. Everything is retail so I have all documentation and Install CD's.

To the Problem. My son messed it up of course and now all we get on the screen is a constant 'loop' of the desk top re-loading. The quick start bar and the bottom right is also looping over and over. I can't do anything like open a folder because the loop clears the screen and takes you back to desktop. The only way I can open anything is through Task Manager. Even in Safe Mode I have to use task manager. I'm almost 110% sure it's a virus and have tried AVG anti-virus, Iobit Security 360 as well as Advanced System Care professional to no avail. All these programs find Trojans, and other nasties and proceed to eradicate them. I've done this many times and it seems I can't get rid of these viruses. I've rebooted after every cleaning. BTW I found 11 Viruses called Trojan.Vundo and one called Rogue.cax

I know what Vundo does but not sure what to do about it.

I have now decided to just re-format the drive. Unfortunately my two CD/DVD drives are not being recognized when I try to boot from disk. I looked for them through Task Manager and couldn't find them in "My Computer". They're gone. So now I can't re-format or re-install windows.

Thanks in advance for any help.