Slow OGL under W2K

I have a little test program for a system that I am writing that simply draws lines and points and uses GLUT to swap a double. This ran fine under win98 but now i have upgraded to win2k and it is running really slowly. The buffer swapping routine is the slow bit (it is a glut function) and it is definitely something to do with ogl because it runs about twice as fast (but still much slower than under 98) if I use some very old OGL libraries (from 1996). I am using an ATi Rage Pro card but have also had the same problem with a GeForce2 MX and a TNT card, and other (commercial) gl programs run fine.
Any help or ideas would be much appreciated.
James Murphy