For SMP client(s), uninstall via 'add/remove programs' in the control panel. For console client(s), simply delete the directory the files are in.
For GUI client(s), uninstall via the uninstall feature found under the Folding@home tab in the start menu.
Before uninstalling remember to run the client with the -oneunit flag to prevent it downloading another WU, this will save wasting a WU. In case you don't know how to do this, stop the client, find the Fah executable, right click it and click 'create shortcut'. Right click the new shortcut and click properties. In the box named 'target', add ' -oneunit' (note the space) at the end of the path (keep it inside the quotation marks). Restart the client from the new shortcut and the client will run with the oneunit flag and will finish it's current WU and stop - then you can uninstall.
If the client is set to run as a service, follow the steps for the oneunit flag but substitute the ' -oneunit' flag with ' -configonly'. This will run the configuration script and the first question it will ask you is if you want to uninstall the service - you would answer yes. After that, just leave everything else as it is and run through the configuration until it finishes.
If you need any more help, just ask
