Crashing continously...WINDLIGHT working hell?

Hello I have a friend who is crashing continously, sometimes he is able to stay on three hours without problems and sometimes he crashes every five minutes.. this happens every day after he has installed Windlight. He as upgraded his graphic card and tried several setting changement but it simply doesnt work.
This is his PC configuration: AMD Athlon 2800+, 1,5 Gm of ram, ATI 9600 Pro 128Mb video card, 250 GB Sata harddrive
Does anyone of you have had similar problems... any suggestion how he could fixes this?
Thanks for any help

: )

Yes I have the same problem, but only the past two days. I didn't change anything in my configuration. I didn't change my graphics driver too. Just since a day or two: poof!

My specs:

Windows Vista™ Home Premium
Intel(R) Core(TM)2 CPU 4300 @ 1.80GHz (2 CPUs), ~900MHz
2046MB RAM
DirectX 10
NVIDIA GeForce 7600 GT