I installed some applications (3D games) which should not affect Maple. Thats why I dont want to try an older system restore point (well, it would be my last option).

Nevertheless your hint seems to be quite useful. Probably the windows firewall or anti-virus software has changed something due to weekly updates.

Moreover official Windows7 updates or Java Updates might have caused this problem.

All other applications stress the CPU when running (as they should). But my Maple doenst want to annoy my CPU :P

Now I contacted Maple Support awaiting their reply. Perhaps they got a solution.

Now I upgraded to Maple14 but still got the same problem. Probably somebody knows a fix for this problem. Otherwise I really have to contact the tech support.