Most of you might already know that the current release of GameGuard provided by the Luna Online patcher is not compatible with Windows 7. Here's a little workout you might like to read. It worked fine for me on Windows 7 32bit.
1) Download my patch
2) Extract and insert the files into C:\gPotato\Luna Online\
3) Run Luna Online
Game Guard will appear with its updater in the upper left and the splash in the middle of the screen. It might take a little bit until the black Luna Online Window turns into the login screen.