Vista and HalfLife 1

All I could suggest is download the newest catalyst driver for your video card.

http://downloads.guru3d.com/download.php?det=1562

I had HL1 running in the pre-RC versions, so there shouldn’t be a reason why this won’t work.

Disclaimer: I’m not responsible if you computer explodes, catches fire, or some other act of god occurs resulting in a meteor blowing a hole in your computer, blah, blah, blah, etc.