Computer won't install (seemingly) any operating system.

OK, I'll chime in...

Too many "weird" problems and I have had the same/similar situation in the past.

Your clue is "old system" - so, is this "old" as in perhaps the motherboard was one of the many thousands produced with faulty capacitors? What you describe sounds like what I experienced...all due to swollen (defective) capacitors on the mobo.

Open it up and look at all of the caps on the mobo. If any are swollen (barrel shaped) or the top is puffed out, that could be the problem.

Regards,
GEWB

At which step does it fail: Clean Install Windows 7.

You've been given about everything possible to work over so I'd just work back through the thread to do everything suggested.

In addition check for newer BIOS update, if none reset the BIOS to defaults: Clear CMOS - 3 Ways to Clear the CMOS - Reset BIOS.

Test the HD with maker's HD Diagnostic extended CD scan, then wipe it again from the same disk.

Posting back with a solution. After running memtest for countless hours without error I removed all but one stick of ram. And went for a Vista install. I held my breath as it successfully completed every step of the installation, and I'm running Windows Update as we speak.

I'm suspecting the problem was a bad RAM socket on the MoBo (something memtest wouldn't pick up on). Now my only dilema is reinserting the memory.

Now that I have Vista running, I don't have a way of being certain which socket is bad (3 socket MoBo), and with 512mb of ram it's sluggish to say the least. Will I be fine reinserting the memory for now?

Why did you install Vista? If it's all you can install then try running the Win7 installer from its desktop to overwrite C as this often works if nothing else will.

gregrocker said:

Why did you install Vista? If it's all you can install then try running the Win7 installer from its desktop to overwrite C as this often works if nothing else will.

I was reading somewhere that XP and 7 restart during installation more than Vista (not sure to what degree this is true). I'll probably go ahead and due the upgrade in time, but for now I'm content that it turns on and runs.

My final diagnosis is a compound issue. I propose that one stick of RAM had gone bad as well as one of the memory channels on the MoBo after playing around with the seating of the memory. One of the sticks was some Kingston Hyper Blue, so we'll se how they deal with the lifetime warranty when it comes to ancient RAM.