Parallels 8 Windows 7 not recognizing change in ram

I just upgraded my older macbook to 8 gig ram. I set parallels to use 4 for Windows 7 32 bit, forgetting that it cant use it all. I shut down windows and changed the ram setting to 2500, but when I go back in, Windows still says it has 4 gig ram, 2.75 usable. What do I need to do to fix this?