My parents HP Media Center system running Vista Home Premium died over the weekend. I can boot to a UBCD disk, but I cannot boot to a Symantec Endpoint Recover Tool disc which runs Vista. I have used the UBCD disk to check the ram and the drives, and found no issues. I have disabled the onboard video card, onboard nic, onboard audio, pulled the modem, and removed the hauppauge card, all to no availl.
I only way I know to test the CPU if it is bad or not, is switch it to a "known" good working compatible PC and try it. If it works, than the CPU isn't bad. If it doesn't work, than you know it is the CPU. I haven't seen any test equipment to verify the CPU is good or not.
It could also be a memory issue.To test faulty RAM try using only one stick at a time and try each stick in each and every slot on the motherboard. This will rule out either bad memory or a faulty motherboard. Failing that, try removing all non-essential components and replacing each one by one to locate the faulty component. This includes everything except your motherboard, CPU and RAM.
If you've been through everything on this list and still have no luck then you're down to your motherboard, CPU and PSU. These can only really be tested by substitution - just swap each part one at a time until you find out which one is faulty. Hope this helps and post back to let us know how you get on.
I have tested the memory with memtest86+, scanned the drive with chkdsk, and with ubcd and found no issues. I have removed the modem, hauppauge card, and disabled the onboard LAN, Audio & video. I also ran the windows memory test from the UBCD and found no issues.