Instructions
Click on Start and select Control Panel. Click on the "Uninstall a program" link in the Control Panel window.
Scroll down the list of installed programs and click on the "Flyff Online" entry. Then click on the "Uninstall/remove" button at the top of the window. Follow the instructions to completely remove the game from your computer.
Visit the Flyff game client download page on gPotato's website (see Resources). Click on the "Download here" button to download the program onto your hard drive.
Double click on the downloaded file and click on "Next" twice to install the game on your computer.