Hi,
i have been playing this game since April, I recently switched to a backup computer and the following happened:
Downloaded SK local client ( non-steam non-browser), installed, ran fine for 2 days then for no reason I can find:
Launch from desktop icon, Black screen, return to desk top.
Consistent.
I followed the instructions in post: http://forums.spiralknights.com/en/node/48
Updated vid drivers, java, de-installed and reinstalled the game.
Did the regedit option, now it does black screen in a small window, then return to desktop
Consistent.