Delay from my 8800 GTX?

Hi:

I recently went through a massive reno, during which time I packed away my computer, and now, four months later, for some reason, there seems to be a lag in the display. For example, when I maximize a window, or even go to print preview in WORD, there's a minor delay in getting the image onto the screen. I have an XPS 720 quad core (6600), with a Nvidia 8800 GTX card, and I've never had problems like this before. There's always been the 'famous' buzz when scrolling or minimising / maximising pages, etc., but never a delay.

Can someone help me with this? I've checked my driver and it seems up to date.

Also, since updating to SP2 on Vista (32-bit), I notice that my RAM is way up. It used to stay at around 28% usage (I have 4 gigs in total), but now it gets up to 40% or even 50%. Would this be causing the problem?

Thanks in advance!

Ken A. Dienne