Driver download

I have a laptop with ATI Mobility series video card.  I have sims 3 on my computer and it's always worked fine until recently, this last week it has been crashing within 30 min- 1 hour of being on.  I did a diagnostics test and it says I don't have a high enough processing speed.

My computer says I have 1.66 GHz and the game needs 2.00 GHz.  Will downloading a driver update from Dell or ATI fix that problem?

When I look on Dell's website it says that the latest version I can download for my laptop was updated on 7/13/2006 which may have been BEFORE I got the computer so is it even worth downloading?  I got my computer sometime in 2006 I think, it's been so long....

Is there somewhere I can get a new version that will update my processing speed so the game will stop crashing?

And I don't know if there's a reason it started crashing recently and hasn't been doing it all along? 

I sent the Sims 3 people an email about it in case there's something on their end they can suggest, but if it's my processing speed I know there's nothing they can do, help please!