Slow XP computers local or network use

Hi,
I have 15 new Dell GX 240 P4 1.8ghz, 512mb machines with XP that are woefully slow. When a user right-clicks to get the properties of a desktop icon it will take 30 secs to display. Saving files to their network folders takes even longer sometimes. Printing can be even slower. I have a 150 node network, with a W2K(PDC) file/print server, a NT 4.0 exchange server and a NT 4.0 file/print server. Any ideas? I thought network, but they can’t even pull those properties off the desktop, so I’m kinda stumped. TIA.