questions

I've had some problems last week with a new video card and it's not much
better now.I've been running the game for two years on a AMD Sempron 2400+
and an nvidia FX 5200 and never had any problems.I've changed for AMD Athlon
XP2800+ and change the motherboard.I wanted a better card so i bought a
Radeon 9600 series.The game was freezing so i had to download Catalyst it
worked fine for about four days and then the game became almost
unplayable.I've change the card for an nvidia 6200 same thing.
The guy who takes care of our computers reinstalled windows couldn't even
open the game,had to reinstall windows one more time.Now,i only have Sims2
installed and it's worse than before with his card a Radeon 9600 family.

I have his computer here a CPI express with AMDAthlon 64 proc 3200+,2.01ghz
and 1.00gb of ram.I've installed the game and all the expansions.It's
choppy,it doesn't run like before and i don't know why.I just can't
play.Could it be the processor?Is Sempron better than Athlon?Are the pieces
in the computer not compatible?
I don't know what to do anymore and i'm desperate and it just cost me an arm
and a leg for nothing.
Any help would be appreciated,
Thank a lot,
C