game graphic issues

Hey, I've been playing guildwars a long time without any problems until recently, my game has graphical glitches like Large sections of 1 color just make choppy shapes all over my screen (not present in screen shots) and the game lags really bad. I thought my drivers were out of date but i have the most recent updates, I redownloaded the game 2 times now, deleted my dat, tried a lot of things, but it keeps happening,

One Major symptom I am seeing is my screen resolution keeps changing, and the colors change, I look @ desktop properties and it is only at 4 bit colors, and locked there. I noticed whenever this occurs it never lets my game play, and I doesnt happen all the time. Why does my comp switch color quality and resolution? Thanks

~Unreal

Does this only happen in relation to GW?

Are your videocard drivers up to date?

Did you change anything in or on your pc? Like new hardware or a clean os install?

It only affects guildwars, but other games on my computer have been running really slow (and i think it could be related)
Also, i clicked the button that auto checks my drivers to see if I need updates (i'm not great @ checking if my drivers are updated, not exactly sure how) and it said I was up to date.
And no i have not changed anything on my Pc other than the moniter a few months ago. The problem affects guildwars the most, to a point where it is unplayable. It worked fine for like a week and just stgarted up again this morning.

Is the computer packed with dust?

like Bob ^ says.... what kind of temperatures are you hitting whilst gaming? If it's overheating it could be causing what you are seeing. What are your system specs?

pretty sure it isnt dusty but im not sure how to check the temp on it.

There is not enough information in the OP's post to do anything other than guess. Which video card? Which driver version? SLI/Crossfire? What OS? What monitor/Resoulation?
Shoot, this could even be a hard drive issue affecting the windows swap file, right now everyone is just guessing.

Given the lack of system info from the OP, I'd say that it sounds like a problem with either the graphics card, or the motherboard chipset, if it's integrated graphics.
In either case, it's most likely a hardware fault either caused by overheating (clean the dust bunnies out of the computer) or a faulty component.
I had a similar problem with my daughter's computer recently. It was spontaneously changing the vertical refresh rate. The cause was a bad video card.

a friend of mine woh knows computers pretty well instructed me to change some settings to lower the amount of work my comp has to do, He thinks my comp was sacrificing graphics to save itself (much like overheating). It has worked since, and no problems. I think it was just drawing too much and i might have a heating problem now that its getting pretty hot at my house (another symptom i noticed). thanks all--ill post again if it ever comes back