gmod black screen

hi, sorry if this was resolved somewhere else, but i searched on google(couldnt search here) and couldnt find anything that helped me.
well this is the problem;
if i start gmod, the screen will be completely black and it wont go back to normal, i can hear the noise from the menu when you put the mouse over them but i cant see anything.
also, if it’s not the black screen it’ll be the last thing i saw in game.
and if the game happens to work, if i go in single player and build something it will randomly make the hud go away, as well as my tool/weapon im using, it will come back up after a little but it’s annoying and i dont’ know how to fix it.
i’ve tried reinstalling gmod and i’ve uninstalled steam and downloaded css and gmod all over again 2 times now, still nothing.
i’ve changed the directx level to every one i know, still nothing :confused:
gmod worked before this, it just randomly did this today.
my system specs are;
core2 duo e7500 @ 2.93GHz
ati radeon 4650
2gb of ram
windows xp

anyone know what could be wrong?

EDIT: nevermind, i fixed it
it had to do with anti aliasing, i had to turn it off in gmod and set it to what i wanted in catalyst control center
weird though since i always had it enabled in gmod
maybe this will help anyone else who had this problem