Fix ALT+TAB in Windows 8.1

[Marco1]

Hi to all, my first post in this blog
I've Windows 8.1 and the keys combination ALT+TAB doesn't work properly.
This combination actives the function to switch from one window to another.
The problem is that this function remains active for a very short time and I'm not able to select the window I want to see.
I tried a restart in safe mode and the function works properly!
I think the problem is a Windows service because the situation repeats identically with a clean install of the system(no driver or applications installed).
Please help me!