Monitor turns off but the PC keeps running?

First of all I apologize if this is in the wrong section. But this issue has been driving me crazy for the past few days. The thing is with my PC (writting this with my Laptop as you can see) For starters here are the PC's specs:

- AMD ATI Saphire Radeon HD6950 2GB
- Intel Core2Quad Q9550 2.83Ghz
- RipJAWS Gaming series 12GB RAM 1600Mhz
- MSI P43-C51 (I know that this is an REALLY OLD motherboard)
- Samsung Syncmaster P2350 '23
- PSU RaptoX 750W

The PC turns on fine, gets to the loading screen, I sign in and all...but after a few mins...5 tops, the screen just shuts off, the orange light stays on (but on the screen itself "Analog/Digital" keeps changing like the signal is temporarily lost or something.) Also pressing the NUMLock or Caps lock keys does nothing. The PC is running but not responding at all. I've completely cleaned it with the compressed air can, so dust shouldn't be an issue. And another thing...playing a game is unimaginable, then it immediately turns off and freezes. So browsing, looking through files...it can keep going for a short period of time, and then turns off, but if I manage to be quick enough to play a game, immediate screen shut down.

The temps of the GPU are around 50-55
HDD maximum reach is 41-42.

Also, the fan attached to the CPU isn't spinning, but even before this I've had issues with it and the PC ran fine.

Forgot to mention...I tried it with another monitor (Samsung T220HD) and the same thing occurs.

Help...anyone

Yard Dog said:

Hello Jeff . check your power options . Go to Control Panel and see what you have it set for

Everything is in order. I'm lucky enough to get enough time to open the Control Panel because the screen shuts off quickly, and ofcourse I have to reset it to get the monitor to display anything again. Didn't set the monitor to go to sleep in the CP, or for it to shut off. Thank you for the suggestion but already tried it.

Yard Dog said:

Seems to be a power issue.. so, to trouble shoot that.. I will defer this to the experts in this area. They may want you to open up the case and check connections , but, I hesitate to say for sure what next step is..

I have a feeling about the PSU as well...but it's strange...a few days back..July 1st when the PC was still filled with dust it ran fine, the screen didn't shut down that often...I mean would run fine for more than 2 hours (with games) but when I cleaned it with the spray, perhaps I slightly disconnected pins from the GPU or PSU...if that were the case then the PC wouldn't start up at all and there would be no signal at the start.