Hoff: That doesn't look like a problem with the power supply, I had the same problem a few days ago. It was caused by drivers which didn't support all the DX Textures. However, some cards don't even have good drivers so you get results like that.
Yeah, I'm not very good at computers so I might be wrong. However, I did try different drivers, and I reinstalled them and all like.. 15 times (and I'm not even kidding). I made sure to delete every single part of the old drivers and so. It still didn't want to work so it was something else than the drivers..
I realised that my power supply was embarrasingly weak though, and I just couldn't be arsed to buy a new one. Now I use a Geforce 4 while waiting for a new computer. (I'll get one later this summer).