For some reason I'm not sure when it started but whenever i try to watch videos in the .avi and .mp4 format i can hear the sounds but i can not see the video. i've tried reinstalling the players and using different players but the same result.

My computer is a laptop sony vaio vgn-270g
2 gb of ram
t7200 intel core 2 processor
nvidia geforce go 7600 gt video card

Thank You for all who responds
(i will be gone for a week but once i get back i will try everything i read in this thread)

Try downloading the K-Lite codec pack (Full edition)

right click on your desktop then choose Nvidia control panel and configure your display card...enjoy

Thanks RJCO It ended up being a bad setting in my NVIDIA Control Panel