I already mentioned that it occurs sometimes, so i did the test 2 times, one while it was working, and one while it wasnt
So here they are
Test when keys worked: All keys worked perfectly
Test when keys were unresponsive: Shift, CapsLock, S, F, J, K, L, 1, 3(numpad), left arrow key, backslash, pagedown keys didnt work D:
Any ideas what it might be?