I second that. My machine also has 4 Gigs of RAM, and since it's XP x64, all 4 are fully recognized. With no memory hogs running and but a couple of dozen windows open, after creating 2 desktops it claimed that "not enough storage" was available (sic, whatever that means). So I logged out and back in, and behold, I was able to create 3 desktops now before the resources ran out. Sorry, I prefer VirtuaWin anytime. One has to wonder, though, why the API functions used in Desktops (CreateDesktop(), SwitchDesktop(), ect) haven't been used by any Windows Multiple Desktops Tool so far.