I have an HP M8000 tower that was running but was super bogged up (slow, spyware, needed defrag etc), it was my brother in laws and they asked me if I could get it going for their kids to use.

It has been unplugged and sitting in a corner since Thanksgiving, pulled it out a few days ago to start working on it and when I press the power button the fans fire up I hear the hard drive spin up, etc but nothing happens on the screen its black and no cursor etc.

I replaced the cmos battery thinking maybe that was it, no change, also changed over the motherboard jumper to clear the cmos as described here (but still no change)
HP Pavilion Media Center m8000 Desktop PC series*-* HP and Compaq Desktop PCs - Motherboard Specifications, MCP61PM-HM (Nettle) - c00906137 - HP Business Support Center

Then I pulled both hard drives (C-os and D-storage) and hooked them upto my main pc via usb/sata cord, ran defrags (both were super fragmented) and also ran spybot and avast scans) found some temp files that were infected and a few tracking cookies but overall nothing serious.

On about 1 out of 20 attempts I was getting a screen that said

Bios Rom Checksum Error

Detecting IDE ATAPI Decivce

Detecting IDE ATAPI Decivce

Detecting IDE ATAPI Decivce

Found CDrom, boot from it ...


But the keyboard would not respond to let me into the bios or anything. on most attempts lights up, fans power up, no error beeps of anykind just nothing, monitor stays in sleep mode even.

Since changing the cmos battery and doing that jumper reset of the bios I have restarted it a good 30+ times and have not gotten that screen again, so at this point I am just stuck at a black unresponsive screen.

I reseated the cards and ram, double checked all the power and sata connections, even tried disconnecting the cdrom and secondary hard drives, and only having the main C-os drive connected, even tried other power connector on that drive, results end up 99% of the time that everything appears to power up but nothing comes on the monitor.

Pretty stumped at this point and was wondering if anyone had a suggestion I could try?

Bill

I would try another PSU. Fans spinning only indicates the presence of +12VDC. The PSU is also responsible for supplying +5 and +3.3V.