"Blue screen" & the end...
When you play MU Online, I strongly recommend you turn CIS off.
Because MU Online has it's own firewall which is 'Game guard'.
It prevents from hackings, game file modifications, game hacks based on software etc.
(for your guidance, there are hacks based on hardware devices)
There is a confliction between 'game guard' and CIS.
Also you may have a lot of problem with other security products including antivirus.
Some antivirus tools diagnose game guard as a rootkit, but it's a FP(false positive).