Computer Hums, Throbs, Clicks: Monitor Loses Signal

[GeoffryTC]

HP Desktop Pavilion Windows 7 (2 years old)
8 GB RAM
Intel Core i5 CPU 750 @2.67 GHz, 2668 MHz, 4 cores, 4 logical processors
Graphics are GeForce GT 230 with 4 GB total video memory available.

In the last month, my computer has been acting strangely. After anywhere from an hour to many hours of use, usually with intensive tasks like games, my computer's monitor loses its signal, with the sound lasting only seconds longer. This forces me to turn off the computer's power. This incident is usually preceded by the computer making strange (sometimes loud) noises, including buzzing, whirring, clicking, and popping.

I have tried the following in attempts to fix it:

Different power supply.
Thorough cleaning of the inside of the computer with a can of compressed air.
Less power-intensive options.
Upgrading drivers.

The fact that the issue seems to be getting worse with time suggests either dust or an old failing part, but it can't be dust because I cleaned the computer well, and I tried replacing the power supply. I ask this forum because similar problems I found on Tom's Hardware seem to be either dirt or PSU failure, and it doesn't look like this applies here.

Help would be appreciated. Here are some people who seem to have the same problem I have, I have read them, but maybe you could see something I couldn't.

http://www.tomshardware.com/forum/317127-33-losing-signal
http://www.tomshardware.com/forum/321413-33-moniter-losing-signal-playing-games-computer-freezes
http://www.tomshardware.com/forum/302554-31-monitor-randomly-shuts
http://www.tomshardware.com/forum/327820-28-losing-signal
http://www.tomshardware.com/forum/301171-33-random-signal-loss

 

[stevetheutilityman]

It sounds like a power supply problem. If you know someone who builds their own pc, have them check it out. And second is the cpu fan, gpu fan or internal case fan failures. Check on those, failing fan makes really loud noises too.

 

[GeoffryTC]

It sounds like a power supply problem. If you know someone who builds their own pc, have them check it out. And second is the cpu fan, gpu fan or internal case fan failures. Check on those, failing fan makes really loud noises too.

I thought so too, at first, but I put a brand new power supply in, and it still happens.

 

[erunion]

That really doesn't sound PSU related.

Sounds like a gpu problem, perhaps a gpu fan related problem. Do you have a different gpu you can try?

 

[GeoffryTC]

I'll try that, that was my next guess. Is there a way to run a computer without using the graphics card? That might help pinpoint it.