Download Sandboxie and install whatever it is you're thinking about in that. It has no access to your real system and works by creating another directory structure within a sandbox folder. If a program wrote a virus to C:\windows\explorer.exe, then Sandboxie would copy the file it tries to write to into the sandbox version of the directory structure and then let the virus infect that, and not the real file. The real files remain the same though and at any point, when you're bored of the software you installed into the sandbox, you can delete it. Remember that when you delete the sandbox you're only deleting the temporary sandboxed stuff, not the real system stuff.
Piece of cake. The software has miniscule resource requirements.