PC won't boot

[BDBondy]

PC doesn't boot, 4 beeps and corresponding red light on front. Any ideas? I've read that it could be the BIOS and that it could be the motherboard. Vendor states it was a working computer. I had to add memory, CPU, and HD. I've tried 2 different CPUs, and 3 different sets of memory. I pressed the CPU reset button as well. Thank you.

[BDBondy]

I'm thinking maybe it doesn't like a 4570 CPU and requires a 4570T? Is that possible?

[itsmyname]

@BDBondy -- found on the Internet by a Bing-search for "HP Beep Codes" ...

HP Z400/Z600/Z800 Workstation - Diagnostic LED Codes | HP ...
http://support.hp.com/us-en/document/c03599666

The Diagnostic LED blinks red 4 times and the system beeps 4 times (once per second), then a 2-second pause follows. This indicates power failure.

Have you tried a different power-supply?

[BDBondy]

Thanks for the response. I'd read that suggestion as well. The vendor says I need to use a 4570T CPU, not the plain 4570. That does seem likely. I appreciate your response. This was the first time in 35 years of working on computers that I ever posed a question to a forum.