Hello,
I have tried to play with another keyboard, a simple one i have for backup and i haven't faced any problems at all. But either with Challenger Pro in the past and now with Challenger Ultimate, i face this problem.
The problem is that the keyboard in irregular times (most of the times when i have my chrome or firefox browser on and in the same time i play World of Warcraft or in the past Elder Scrolls Online or other games) becomes unresponsive and no key work at all. If i try to disconnect keyboard from the usb or from its connector in the back of the keyboard, then my pc goes frozen and i have to restart it to go on!
So my only other option is to restart my pc with reset button and not disconnect the cables (as the result is the same)
Now, when i play without any browser on, the problem seems that doesnt happen so often. But it does happen again, but not so often.
Also let me state that my pc config is: I7-3820 CPU - 3.6GHz, 12GB Ram,, 64Bit Windows 7, GTX580 1.5GB Graphic Card, 2 SSD Disks