GF2 GTS lockups

In my sig you will see my 2nd rig has a GF2GTS(still a great card!).
It has served me well for a while now but since I slapped it into the 2nd rig I get lock ups in a few games and sometimes mpegs/video/divx.

Currently I am using 40.09 drivers. I have tried 40.72, the 30's and 29 and have been getting lockups.
Some games play fine like Morrowind, AofE, UT..but some games do not play well: MOHAA/Spearhead, BF1942, UT2003.

Any ideas?

basically my first rig plays games fine and the 2 rigs are pretty similar.

It's probably heating up alot, try slightly underclocking it and decreasing some settings/resolutions in those games. They seem like they would put quite a load on the ole gts.

Is that rig overclocked at all? If so try lowering the overclock...maybe them games get errors due to this.

If not try really old drivers and see if that sorts things out.

Thanks guys...no the rig is not o/c'ed any more nor is the video card.
I cant imagine a Modded TtV7 allowing a 1g duron to heat up! it is possible that the vid card may be heating up but after 2 years of use I never had this prob. I will admit that the case is crapola for cooling so at present i have the side off.

I was thinking that the new drivers may not work well w/ older GF cards...but than again maybe it is heat...time for a fan mod on that card.

Any other ideas?