Need more RAM

DB has been working on his blue PC for ages now.  It konked out for no reason, he then installed Vista but some of the trading programs he is using are not compatible with Vista.  He then reinstalled XP and is working fine but it needs more ram to speed her up.  I told him he should invest in some bucks to get some RAM since there are at least 3 more slots for more RAM.  I’m hoping he will get it done when i’m on vacation so I won’t be hearing his grumps on “this POS is driving me up the wall!”