Microsoft VirtualPC is a program that creates a virtual PC within a window that is isolated from the rest of the machine -- it's like having two (or more) computers at once. Microsoft is giving away the 2007 version, which runs under Vista. VirtualPC will run a number of different operating systems. I've just installed XP Pro on a VirtualPC running under Vista on my laptop. This is one way to use XP programs that won't run under Vista. The only catch is you have to have a separate license for each operating system that you install.

You can download it here:

www.microsoft.com/windows/virtualpc/default.mspx

Incidentally, from what I understand, VirtualPC will run Linux -- this is a good safe way to try out Linux without having to lose your primary OS.