I have a question for anyone more knowledgeable than I. My computer is acting up now, for instance I'll be on the computer and it will just flash a random color for a few seconds; first it was black, then white, then burgundy, if that matters. Now I'm noticing a slowdown in my games too. They are lagging quite a bit. The computer in question isn't custom built, it is actually bought. It is an HP m9150f, however the graphics card is an Nvidia GeForce GT 430. I just wanted an opinion on what to do; if I need to replace the PSU or the GPU. Any help is great!
The fan is running, but hasn't been cleaned out in about a month or two. I was planning on cleaning it out next week.
That's probably your problem, and you might want to remove the heatsink and re-apply some thermal paste and see if that gives you any improvements, you might also want to check the DVI (or VGA, if that's what you're using) connection between the card and your monitor is secure.
While I somewhat agree with the other respondents, if you have cleaned your fan a month ago, cleaning it again will not help. It does sound like a heat problem, but that can be verified very quickly with Nvidia System Monitor, a free tool provided by Nvidia : http://www.nvidia.com/object/nvidia-system-tools-6.08-d...
Make sure you grab the correct 64-bit or 32-bit driver, depending on what OS you have installed.
In my experience, overheating does not cause game slowdown. The game will suddenly crash if your GPU gets too hot, with the screen usually putting up random garbage and the sound getting stuck on one (usually annoying) tone. I would be more inclined to search for malware or other junk which is using up all your CPU cycles.
Download and run MalwareByte's Anti-Malware. You can run the free version. Then also run SuperAntiSpyware, also the free version. Between the 2 of them, they will detect most malware. There are more powerful tools out there, such as HijackThis, but they will require some help to interpret the results.
Next go to Start - Run - msconfig, move to the Startup tab, and see if you have any unnecessary crap starting up. You may have to look up each item if you don't know what it is, but you can improve performance quite a bit getting rid of useless items such as browser toolbars, or BHOs (browser helper objects).
Okay, for those requesting the temp: doing nothing but general but general stuff, the temp is about 46C. When I watch HD vids it goes up to 53C, and playing games it gets up to the mid 80's, but that is in full HD settings is Mass Effect 3. I noticed during game play it seemed to be fine; I don't know if my computer is just being finicky because it is six years old, or if the hardware is just dying. Thanks for all the replies so far!