Hello, I use the Blackwidow Ultimate Keyboard via Bluetooth for a couple of weeks. But suddenly the use of Bluetooth doesn't work anymore. Today I just set up a static colour for the keyboard, but I don't think, that's the reason why bluetooth does not work anymore. Everytime I change the switch to bluetooth, the keyboard doesn't light up. Everything is dark. I also checked the battery status, which is 65%. Then I tried to charge the keyboard with the USB Cable without connecting to a pc. At this time the led for "M" lights up every 5 seconds in a red colour. It is possible to use the keyboard via cable and via dongle. It would be nice, if somebody could help me. Thank you very much.