I don't have 1 gig of ram either, and it runs just fine on my pc, only lags a little in towns full or people, usually the first district in big towns, nothing too major though...
the card he has isn't supported by guild wars and it will tell him that when he installs it. you can still play.. it only runs slow when there's bunch of ---- going on near you.. but in combat areas, it's usually fine. i bought a video card and i still get lag in towns.. everything will look like crap with that card.. but u can still play