Windows XP OS reinstall??

OK folks, I'm completely at a loss.

I have a computer that had the zeroaccess virus and was really messed up. It wouldn't let me do a restore and wouldn't let me a clean install from the Dell OS original Reinstall CD, which I do have.

The computer would still come up, with the original user logged in. However it was still plagued with viruses - or so I think it was. The only disc I could get it to boot with is Hirens. I ran every scan known to man and it found a few and got rid of them but I still couldn't do the reinstall.

Getting really frustrated and tired of this problem, I used Darik's Boot & Nuke to completely wipe the drive. I created an OS install disc on a USB drive using USB_PREP8 and PeToUSB. Changed the boot order for the USB and get "NTLDR not found". Huh?

I assumed it might be a bad USB stick, so I used a different one with the Dell Reinstall disc. Same problem. NTLDR not found. Oh yeah, I did make sure to make the flash drives 'bootable'.

Tried WinXP full install disk which I burnt to each flash drive just in case. No dice - NTLDR not found. Tried the CD's again just for the fun of it - nothing. Blinking black cursor at the top left of the screen.

I would appreciate any input. Thanks in advance.