I have taken the hard drive out and put it into an enclosure and scanned it for viruses offline with KAV and with MSE - both found multiple infections they cleaned. I also ran manufacturer diagnostics on the drive and it passed. I put the drive back in the system and no change. I have a USB CD drive I attempted to boot from, but it exhibited the same problem - cd's began to boot then restarted.
Apart from being unable to boot from any source the system shows no obvious hardware problems - it doesn't make any funny sounds, no funky flashing lights, doesn't shut itself off, seems to display properly. I can get into the BIOS and stay there as long as I want or make any changes I want. It sees all devices attached and at least attempts to boot from them.
never mind, duh - bad RAM. Both sticks. Swapped out, can get to disks now.
Edited by jrmarto, 20 October 2011 - 07:22 AM.