8.1 - Startbutton not working after a while

Hey guys,

yesterday i successfully installed Windows 8.1 and i noticed that my start button isnt working after a while.

What i did: Disabled npu.sys to avoid the memory leak, other than that i did no tweaks or something.

A reboot is solving the problem, but i wont reboot my laptop every hour or so..

i tried the tips from google, but they didnt help - any clue?

thanks