So! I'm running on this fairly decent HP Pavilion dv6, with the Mobile Intel(R) 4 Series Express Chipset Family for graphics...

When I first got this thing, it actually played games perfectly. There was no lag, and the graphics were wonderful. Though, one of the game i acquired didn't work, so I tried a graphics update from HP. The game didn't work.

But that's not important, now ALL of my other games seem to lag! The graphics card can't be physically broken, because the desktop and simple applications and even one of my rhythm games don't lag... but GTA, Combat Arms, PSO and WoW all seem to have received some performance issues SINCE the update.

I tried a system restore to way before I did the update, and that didn’t work. I couldn’t "Roll back the driver" because the device manager didn't know it updated, and spending four hours on tech support didn't help!

TL;DR
Performance issue with games, notably lag/reduced frame rate, after a graphics card update!

The person in tech support said that might be something in the background eating up memory...

But, in any case, what other information should I provide, and what possible solutions can you give to solve this?
Thanks in advance!

What operating system is on this laptop?

Vista 64-bit.