So, my computer has had this as a recurring problem for about a year now. After suffering some form of trauma, (a small child running into, someone tripping over it, etc.) my computer screen will turn a solid color, usually gray or blue. After shutting it down the monitor turns black and attempting to boot up the computer causes the monitor to stay black, though the fans in the case turn on and machine makes various clicks and whirs.

Every time this has happened in the past I have gone into the case, disconnected all outside cables, the video card, the battery on the motherboard, and occasionally other things as well, sort of haphazardly. I let the thing sit for a while and then plugged everything back in and after maybe one or two iterations of this process the thing eventually booted up.

After it's most recent trauma (having a laptop dropped on it =_=; ) it hasn't booted up properly after several unplug-and-replug-everything routines. The fans still start up, like before, but I haven't been able to get video to work. I have tried disconnecting the video card and plugging the monitor into the built in graphics on the motherboard but that still didn't work. While "on" I tried pressing various "locks" on the keyboard and found that numlock caused a light to light up, but neither caps nor scroll lock did ( I don't know if this means anything, but I figured I'd throw it out there ). No sounds are emitted by the speakers, but I don't know that any are normally on bootup. I attempted to blindly enter my password an log in, but this elicited no change or sound from the speakers.

I recently rebuilt my computer, and the only thing that're still really old in the case are the power supply and one of the two hard drives, which are five years old (came with the original case). Could this problem possibly be rooted in the power supply? I am thinking about replacing it anyway, as I want a new case with better airflow.

Parts:
Motherboard: Gigabyte GA-G31M-2L
Graphics Card: KFA2 Nvidia GeForce 8500GT PCIE
2 x Kingston KVR800D2N6/1G 1GB 800MHz DDR2 Non-ECC CL6 DIMM
Dell HP - P2507FW Power Supply (250w)
12v DC 1.8A Nidec TA350DC Cooling Fan
12v DC 0.6A Intel DTC-AAM13 CPU Fan
Intel Celeron Dual-Core E1200
Western Digital WD1600JD - 75HBB0
Western Digital WD4000YR - 01PLB0

Yes replace the old power supply and back up everything important to you. Get those old hard drives replaced ASAP. They are slowing your system down at the very least

I replaced the power supply with a 650w Corsair and after resetting the CMOS have been able to run onboard graphics.

Does it load windows,, but windows is black.

Then thtas a monitor issue...

Hey Tweakboy,
He is running on-board graphics. The computer boots... We can say he is in Windows

Yeah, it works now, I posted in another forum, and they told me to short the pins that reset the cmos and I did that, and it worked, but as both of you guys said I needed to replace the psu I went ahead and did that. Now my computer seems to be working fine except that the temperature probe on the motherboard seems to have burnt out: it reports that the system is running at -1 C which it most certainly isn't. Is this an irreparable problem of the motherboard? Since the computer can't track cpu temp I went ahead and told the BIOS to set the CPU fan to always spin at max.

Thats great miyamamo. Don't worry about the temp sensor. Most motherboard sensors are not accurate. Download Core Temp to check your CPU temps

Core temp says the temp is 20-30 C at all times, which also seems like a lie