OS Paged Pool

Lately, everytime I join a server, Gmod closes and this comes up. I know there’s a URL, but it’s really messy (according to me), and it would be nice if someone could help me.

Picture - http://i28.tinypic.com/1zgb6tj.png

Computer specs, please?

Dell Optiplex 320
Intel® Core™2 CPU
4300 @ 1.80GHz
1.80 GHz, 1,00 GB RAM
PAE (Physical Address Extension)

(I know, it’s the suckiest ever, but I’m about to buy a monster computer)