Have no fear, Sin's here!
I'm going to assume you're using vista/7 if you aren't just ignore the first step
Right click online.exe and then click run as administrator
Click "Options" and look for Window Mode with a check box to the left
Check the box, make sure it's checked, and click save.
![Image](http://i1199.photobucket.com/albums/aa470/seniorsuave/Untitled.png)
Should look something like that, aside from the resolution, unless of course you're going to use that setting