I installed X-Lite on a 64-bit Win 7 machine. Install seems to go smoothly, then when I launch the application, its splash screen appears, then it goes away, leaving a tray icon with the familiar up-and-down-arrows icon that software has. (I used previous versions of it up until 3 years ago with no problem.) No client window, no nothing. The tray icon is completely useless -- it has no context menu, clicks and double-clicks do nothing, only the name "X-Lite 4" appears as a tooltip when I hover over the tray icon.
All I can do is terminate it from Task Manager, under "End Process".
I get the impression X-Lite actually is drawing its window, but in an old GDI fashion that befuddles Win7's funky graphics subsystem. Does that make sense?
EDIT : It finally did display its main window -- some 15 minutes after I launched it! Maybe it got borked while auto-probing the firewall for its NAT settings?