BleepingComputer Review:

The F-Secure Uninstallation Tool will remove F-Secure products from your computer in the event that you are unable to do so via the Windows control panel.  When you run this program it will perform the following step:

•  Stopping the services
• Cleaning the system registry
• Removing the files and directories
• Restarting the system

After the reboot you will no longer be protected by F-Secure, so be sure to install another anti-virus program as soon as possible.