usually before i got my Radeon 9550, NS would never freeze, but now that i have it in, the game usually freezes. the time in which it freezes is never constant, sometimes after 15 minutes of playing, sometimes 10, and sometimes right when i join a server. here are my stats.

2 GHZ
Radeon 9550 (256 DDR)
Windows XP home ed.
using steam
counterstrike retail client
newest version of NS, beta 5 i think.

please reply soon. thanks

Make sure you have the latest drivers for your card.
Make sure you have the latest chipset drivers for your motherboard.
Sometimes freezes can be caused by a virus or spyware.
If you have an old power supply, buying a newer graphics card can send it over the edge and you won't have enough power to run all your components and it will crash.
You may be having heat problems that will crash your computer.

All those things can crash your computer while you're playing.

take ur case off ur pc and have a go - worked for me even tho it will actually reduced the cooling? meh

take the case off your PC and remove all the components from your motherboard and try and play outdoors.