Troubleshooting my computer that powers up but won't start

I have a bit of computer trouble. I have a case-less motherboard computer I'm running every night, out of a plastic bin in the backseat of my car. Yesterday morning I started it up, let it sit at the Windows login screen while, then for no apparent reason the computer powered off then tried to turn itself back on, but it couldn't start.

I'm having trouble diagnosing the part that's malfunctioning. The keyboard displays three steady red lights, indicating that some hardware component is preventing the computer from staring. But everything looks normal. The motherboard lights up, the CPU and GPU fans spin, and the hard disks whir.

The two main culprits to my computer not starting are usually bad memory (RAM) or the graphics card (GPU) not securely connected to the motherboard. I've tested both, but it doesn't seem like they're the problem.

I ran each of three RAM sticks individually on every module, and wiped the contacts with rubber to remove static charge. Computer still can't start, so if it's RAM then all three simultaneously failed. That is possible, but I have never had it happen before.

The GPU lifting slightly off the motherboard is a common occurrence for my computer. Sometimes things bump into the graphics card while I'm driving and dislodge it enough that my computer doesn't start unless I adjust the card so it's seated properly. This was my first guess while troubleshooting, and when that's the problem it has always fixed it. Not this time. I tried the card in both slots, and also tested using a second, older card that I know works. Nothing.

I have left to rule out the power (PSU), and the motherboard itself. I'm thinking there was a power surge that knocked out my computer, and it may have fried a capacitor on the board or in the PSU. If that's the case, then maybe a small amount of voltage gets to the GPU - enough to spin the fans, but not enough to power up the processor.

A motherboard requires a CPU, RAM, GPU, and PSU to boot. That's everything that would prevent it from starting. There's no need to test hard drives; even without them, the computer can start into BIOS.

So I'm looking at cost of about a $30 PSU and/or a $80 motherboard to fix. Not a big deal. Problem is, I'm currently in Stirling, Colorado out in farm country where an entire town smells like fertilizer and there are no computer parts stores. So it won't be until Chicago that I can get to a Fry's or a Microcenter to buy parts I need. That'll be a twelve hour drive.

It sucks not knowing for sure what the problem is until then. On the way are a few sizable cities where I can get to a Staples or a Best Buy for a new stick of RAM just to rule out a memory problem. I might even find an old computer at a Goodwill to strip for a PSU. If I find myself in a nice city and want to stay several days, I could order parts online.

Lots of online vendors (Tigerdirect, Newegg, Fry's) won't deliver to a post office because their shipping only covers residential addresses, but a trick to get it there is to write "- general delivery" after my name and type in the street address of a post office that services general delivery.

I have an old laptop to substitute in the meantime. I forgot how slow, heavy, and unwieldy my laptop is. Hope to have new computer parts soon.

I should probably invest in a good surge protector, to prevent voltage spikes from damaging my computer components. I used just a plain extension cord for seven months without any trouble. I usually plugged in to the exterior of commercial houses at night when no one else was around. Not much danger of damage to my computer then.

But in the morning when my computer went out, I was plugged in at a baseball park that had tall stadium lights. Workmen were maintaining the field and maybe one of them turned on some heavy electrical equipment that sent a power surge through the same electrical line I was tapped into.

I shoulda known better than to turn on my computer in that situation, but I'll know better next time. After I get a nice new motherboard and bring my computer up to date. : )