Return of Reckoning

I am not a new player, I play a lot. Just yesterday hit up two ranks with my Knight. But today I can't enter the game... The program itself works, but everytime I click a taskbar icon, the window maximalize for a second and then minimalize...

My computer and keyboard is fine... I guess.

Can someone help me?

Okay, game works fine after rebooting the system.
Seems just one wierd accident. I felt troubled because the problem has occured despite the fact I've turned on a fresh session to computer after 8+ hours, so any trash/debris processes were not taken into my consideration.