Hey guys I've got a buddy having a problem with windows xp home.

Here are his specs
intel pentium d 830 3ghz dual core
250gig harddrive - ide wd
4gb ram crucial ballistix 4*1gb sticks
nvidia geforce 6800
sound blaster audigy 2 zs sound card

The problem he's having is when he has alot of programs open windows is acting like he doesn't have enough ram to open more. He has had more programs open before but recently it's started getting worse, he has run virus scans and has an active virus scanner. he has checked how much ram he has left, and windows is stating around 2.6 gigs, he is going to run memtest to make sure his memory is fine, i'll update this thread with more information when I get it. Just curious if anyone knows anything that could cause these types of symptoms? His cpu load is very low around 4% he uses programs that aren't very intensive, they can be alittle more cpu/memory intensive if they're open but he has them minimized, but that should be a problem because he's had more open before. I'm open to any thoughts/suggestions and i'm sure he is too, thanks.

I await cordial replies.