This is one I've never seen before and I'm hoping someone can help. I was a computer support person for over 20 years and am now retired.

The machine in question has been in operation for about a year. No changes have been made to the hardware. At power on it runs POST OK, counts memory correctly, and detects the drives. At the point where it should start to boot it stops with a blank screen. There are no error messages. We can get into the BIOS setup and set it to boot from a CD. Same problem; no error messages. The CD is standard IDE and the hard drive is SATA. There is no floppy drive installed. Everything in the BIOS looks normal.

Any ideas?

sound like your HDD is dying,,,,disconn the HDD, and leave the cd drive attach, set bios to boot from CD, if your get the boot screen from the cd then you have a HDD prob..then reconn the HDD, disconn the cd now boot, with the HDD, let us know whats happen......but i do beleive your boot sector on the HDD is dead.

There's no "boot device not found" or "operating system not found" message, so I don't think it's the MBR. It's a simple thing to try, though, so I disconnected the SATA boot drive and it still won't boot from the CD.

If you have a black screen with a flashing cursor in upper left hand corner, then BIOS is having problems detecting a device; most often a drive, but not always. I'm referring to detection as related to ESCD, not the drive table listing in BIOS. ESCD passes hardware information to Windows.

If BIOS will allow you to reset ESCD (redetect devices on boot), try that first.

Disconnect signal and power cables from all drives (could be optical drive), remove PCI cards, and try a boot.

Reset CMOS using jumper or remove CMOS battery.

That may have been it. We unplugged the SATA drive last night and tried a few things before we got tired and quit for the night. This morning we plugged in the drive and it worked. I won't say it's solved until we have a chance to shut down and reboot tonight, but it looks good right now.