Well forget, I have no loving clue how to.
learn how dude, you can find out easily, it's not hard to learn at all if you are open to new knowledge.
shhhh
let the idiot buy a prebuilt
nope, i'm afraid a gtx 650 and 8 gigs of ram can't "run gmod good"
I have a 650 and I run most of my games medium to high. Suits my needs. Just letting the OP know he can get more for less the price.