[QUOTE=rolandc5;2587403]Hi, my computer has been acting up when I installed the HD 4650, my computer just locks up when playing any Source games (half life 2, portal 2 etc.)[/QUOTE]
I’ve heard this on some podcast somewhere. It might have somehing to do with your sound and graphic drivers.
I assume it did work flawlessly when you had your old video card in the pc?
Is the HD 4650 a power hungry monster?
If possible, do a clean install on a fresh hdd and test the source games.