I think he's full of it, 32 bit can handle up to 4GB and Windows can handle up to 2GB without any issues... Don't see why an Athlon XP would be any different, it's a 32 bit CPU in Windows...
Windows can only handle 2 gigs? Ive never heard of this. I wouldnt make sense that the limit would be so low if most boards can handle at least 3 gigs.