Crashing when joining a server

When I join another server after being on a server I get a “hl2.exe has encountered a problem and has closed”, is there any way of fixing this, as I have already uninstalled and reinstalled the game via steam. My graphics card is an Ati Radeon Xpress 200 but I will be getting a new one soon. My gmod plays smoothly in game but I need this problem fixed. I have already increased my virtual memory, could someone help.

[editline]10:49AM[/editline]

Please, this has been plauging me forweeks!