You can remove Plesk as any other program in Windows: go to Control
Panel > Uninstall a Program, select Plesk and click Uninstall.
For the complete instruction on how to remove programs in Microsoft
Windows, read this article:
http://windows.microsoft.com/en-US/windows-vista/Uninstall-or-change-a-program.
You can also remove a particular Plesk component from the Plesk user
interface, at Tools & Settings > Updates and Upgrades > Add/Remove
Components. For details, refer to Adding and Removing Plesk
Components.