how to create & switch between project-specific sets of open windows

Forgive the intrusion of a non-techie but I know this must exist. On a given day I may work on one project that requires software packages X, Y, Z, websites A,B,C, and files 1,2,3. At another point I may want to switch to a different project with an entirely different set of software and file needs. How do I either switch between them or close the one and open the other with just a hotkey click or two? I'm running dual flat panels and NVIDIA on XP. Thanks for any help.