IPhoto not working and graphics slowed after apple software update

Question

I just installed a bunch of updates for my relatively new macbook pro (end of 2009) and found that afterwards the computer's graphics became quite jerky (mainly the screen saver and expose - four finger swiping) while iPhoto shows all my pictures as icons but cannot display them individually or in a slideshow. I've tried copying the photos to my desktop and opening them in preview but I just get a white blank space - I cannot even open images downloaded from the internet. However - I can still access and display these images as my desktop background. So I'm assuming it must be some problem associated with the programs - although that doesn't explain the slow screen saver...
Is there a way to uninstall software updates (e.g. iPhoto version 8.1.2 or 8.1.1)?
There is another possible alternative for the problem:
I was removing a program at the end of its trial period and was looking through system files to attempt to remove any leftover files. The software company is named "Gforce" so, thinking that any files related to that should be unnecessary, I deleted a few files named "Gforce..etc." in "System/Library/Extensions"
Does anybody know if these were actually related to something else entirely? Does anybody without Gforce software on their Mac have these files?
Any tips?

Answer 1

To reinstall iPhoto:
There should be 2 Discs that came with your Mac computer, One is Mac OS X, and one is Applications (The one you need)
Insert the Applications Disc, Reboot, hold the Button that it tells you to hold on while the computer is starting up then there should be installian steps.
Goodluck.