So today I turned on my computer and then waited a bit while I did some other stuff. I turned on my monitor and it said "No Signal" and the light went orange. This was quite strange. So I restarted and it did the same thing. Then I opened my case and saw that as soon as I turned my computer on, the red led on the back of the video card like turns solid red for a second, then really quickly flashes ~ 3 times (it's really fast, so it's hard to count). I have tried switching the port which my monitor is connected to, and there was no luck. It is using a DVI connection. I have also tried using a different PSU connection with no luck either.

I am using an ATI 4800 HD video card. I have a 530 Watt PSU.

Can someone please help?

Also, I cannot try a different video card. My motherboard does not have on board graphics and I do not have any other video cards to test this with.

Funny thing about this. After I posted this topic from my laptop I pushed on my video card to make sure it was in all the way (although, I don't know how it would have come out) and turned my computer on and nothing came on. So I went back onto my laptop and started googling and then all of a sudden the screen turned on and my login screen was there. I had forgotten to turn the pc off when I went back to my laptop and it started working ONLY ONCE IT GOT TO THE LOGIN SCREEN. It did not show anything else, I was sitting right in front of it with my laptop. So I restarted to put the side panel back onto my computer, and it rebooted and froze at the Windows XP logo. I restarted and booted from the "Last known good configuration." Everything worked fine.

Then I went to take a shower later in the day and I locked my computer (Windows key + L) and turned off my monitor and took a shower. Then I came back (I was 100% dry, so I don't think this has anything to do with water) and turned my monitor on and it came up, flashed and went on standby, flashed on, standby, flashed on, standby, then it flashed on but it had a sort of distorted image, then standby and finally came back to a normal signal.

Since then it's been working fine. I assume these symptoms are too random to get any sort of solid diagnosis. However, I think it might be one of these two things:

1. Overheating: My processor runs at ~52 degrees Celsius idle. There's not much I can do about this because I already have 2 intake fans - 1 80 mm fan and 
1 120 mm fan - and 1 120 mm exhaust fan. On my processor there is the stock OEM AMD fan. My video card runs at about 55 degrees Celsius idle. However, it gets VERY HOT in my room and on my case where my power supply is. I can only imagine how warm it is in the case. So this leads me to believe that overheating might be an issue, but again, I don't see how that would apply if my computer wasn't on before I had this problem, so it probably wasn't hot in there.

2. Broken wires: I have examined the wires on the back of my monitor to the best of my ability (cramped desk space) and I can't find any holes or anything. However, we have a new kitten and it loves to play in my room with all of the wires. I noticed that after this problem arose (later in the day when everything was fine) that the kitten was playing with some wires under my desk. So this could be it. If this happens again I will try a VGA cable with a DVI to VGA adapter to be sure.

Any other thoughts? This is very odd.

GPU runs at ~66 degrees Celsius.