I tried reinstalling the game already and that didn't fix it... Basically every time I get to the main menu the game crashes to the desktop.

I recently upgraded to the Catalyst 7.5s and the game worked great before I upgraded. Does anyone else use the 7.5 Catalysts? Does your game work?

You might try disabling the custom gamma ramp and then installing the new drivers.

What the hell is "custom gamma ramping"?

I'm having the same problem, I've reinstalled steam and NS and no luck. The title screen comes up and it crashes.

Could you check what version drivers you have installed?
Go to Start -> Run
Type in DXDIAG
Click on the Display tab
And in there could you post the Version that is listed on the right hand side of this screen?

If you've got the 7.5 Catalysts (that I think I'm having the problems with) it should be 6.14.0010.6698 .

6.14.0010.6683

just installed 6698 and it works

Well I just ran cat-uninstaller to delete all the ATi software off my computer and then reinstalled the 7.5 Catalysts and that didn't help...

Every other game I own runs fine if not better with these drivers but NS just friggin crashes. All I want is to play Natural Selection!

I've had the same problem earlier with different cat versions. You can run NS by going into your userconfig.cfg file and changing the value "cl_gammaramp 1" to "cl_gammaramp 0", or including the latter if it's missing. This will make the game much darker and less enjoyable at least for me, so my solution was reverting to an older driver version.

I changed that cl_gammaramp to 0 in config.cfg and I added it to userconfig.cfg and it still crashes. No luck on that one

roll back driver versions, or try omega drivers