Uninstalling what? The script from the machine? You should just remove the scheduled task from your scheduler. You can delete the script or not. Your machine will disappear from the monitor after 5 days (or 7 depending on the mood I'm in, until I get the automated script working).
If you're talking about the folding service itself, the answer can probably be found here: http://folding.stanford.edu/faq-uninstall.html
To summarize, it sounds like you just delete the folding folder (sounds kinda redundant), and it will take care of itself. However, I'm wondering if it wouldn't be wise to bring up Settings / Control Panel / Administrative Tools / Services, and disable the service first (assuming it's listed there).
I've never done this, so I'm kinda pulling it out of my.... well, whatever.
Thx