(I'm pretty desperate to fix this thing, so I'm going to try to be as thorough as possible)
Before the problem occurred (this may not be important, but just in case): I took my hard drive out to hook it up as a slave (for storage) to a different computer. A new user account was made.
Initially: I hooked the hard drive back up (and the few other things I had to unhook to get to the hard drive when I was taking it out originally) to the computer it was in first. I may have switched some power supply cords around. When I turned the computer on, I heard three beeps. I then found out that three beeps meant a memory error. I didn't understand how I could have gotten an error like that; because I didn't even touch the ram when I was taking my hard drive out. I thought maybe the ram got loose somehow. I then took out the ram and the graphics card so I could get to the ram. Then I put the ram back in, in a random order. I didn't think it would matter, because the ram sticks are all the same (brand and all). Before putting the graphics card back in, I saw a small piece of dust in the pcie port. I couldn't get it out, and I didn't think that is what the problem was anyway so I just left it and reinserted the graphics card.
I turned the computer back on and I didn't get any beeps this time. The computer sounds as though it is starting, and the light flickers like it's doing something, but then disappears. The num lock light is also on during the initial start up, but then disappears. The graphics card fan is running, and it seems to be working, but I don't know how else to check to see if it's working. Everything else seems to be working based on what I know about how to check to see if it's working, but I could be missing something. The monitor shows no signal when turning on and off again. The computer has been running for a few hours, and it sounds as it would sound if it were running normal idle.
Of the steps I've taken so far, I've force shutdown my computer (with the power button, not the psu switch) a least a handful of times. I'm guessing in order to fix this problem I'm going to have to do the same many more times. Is there a risk in shutting the system down in this manner multiple times?
Does it sound like I should try using a different graphics card?
Please let me know if you have any ideas related to this problem.
Any help would be greatly appreciated.
Graphics Card - ATI RADEON HD 2900 PRO 1GB PCI-E 2X DVI
Hard Drive - Barracuda 7200.11 SATA 3Gb/s 1-TB
CPU- Intel Core 2 Quad Processor
Motherboard - Intel DP35DP