computer suddently going slow

I quite recently made a fresh windows 7 install due to recieving a new graphic card. I installed everything from drivers to normal games etc. and everything worked fine. Now I logged onto my computer and everything is extremely slow. The mousepointer is flickering, the text when I'm writing this message is slow at showing up. I was running dual monitor but with it every simple action took 5-10 seconds such as bringing up an explorer window. I can't remember having installed anything, did a virus check with no luck. Anyone know what might be wrong? the computer is completely useless now. Could the graphic card be messing it up? would such a thing result in slow text? :S

There is no reason my computer should behave like this when it's nearly clean, though it's no technical wonder it should run windows 7 wiht ease. the OS runs of an SSD. it has 6gb ram, EVGA Geforce 450 GTS, a 2,8ghtz i7 cpu... I'm at a loss, checked the task manager and all visible resources are running at 5-10 percent.

ok, I'm none the wiser but problem seems fixed for now. After numerous reboots. I did allow the installation of 5-6 windows updates, I can't see how they would cause this though and certainly not fix it as it was fine before them. Pulled out my computers power for a few min, though not enough to have cleaned out bios and such, perhaps the RAM if something was stuck there not entirely sure how long that takes. Made sure my screens was properly plugged in but that was more a matter of pure desperation, cause the mouse was the only thing flickering, rest was just slow so unless monitors got some two way communication with HDMI or DVI I can't see that fixing anything. I did however enter bios and notice something 'interesting'. my fan cooled computer in a room 20C warm somehow managed to cool itself to a point of -25C on the system temperature... Though not sure if I just miss understood since fans were running and no heat inside indicating the motherboard allowed any overheating to take place.

All in all I'm just more confused but with a working computer for now ^^ and ideas of what to do if it happens again is still greatly appreciated though

First thing that popped into my mind was the video card driver. I've had similar problems before that have just required a re-installation of drivers or simply a few restarts.

Most of these problems I find are just part of the mystery of computer operation I suppose. Glad to hear it is working, however.