Are you running Windows Vista or Windows 7? Maybe you're run into the problem where you can't run your legacy applications. Or, maybe your old peripheral (e.g., printer, scanner, etc.) isn't working. Fortunately, VMware allows you to run a virtual Windows XP machine on your computer that's running Vista or 7. This way, you can still run those legacy applications and peripherals. That's what I'm doing. I have an old HP LaserJet printer that doesn't work on Windows 7. It's a good printer, so I don't want to throw it away. I'm now printing to that printer using a virtual Windows XP machine.
VMware gives you much more flexibility over the "Windows XP mode" feature that is built into Windows 7.