Microsoft wireless laser keyboard 6000 v2 ...

i had the same problem, i checked the batteries with a DMM and the measured 1.4v i replaced the batteries with new and i still had the same problem. anyway i ended up taking the keyboard apart and found where the antenna is connected to a push on type connector alongside the pcb board inside the keyboard, the connection was slightly corroded. i cleaned it up and it is working fine know, even with the old batteries.

Yeah, to associate the keyboard, you get to hit the reset one on the transmitter too, then the keyboard.  You doublechecked the batteries and did that by now though, right?

I had a problem with the Microsoft wireless keyboard/mouse 1000.
the green light on the transmitter which would stay lit on F. stoped lighting up. the mouse would work but the keyboard would not.

I tried sveral times to hit the reset button on the keyboard to no avail. put new batteries in. still nothing.  however i just tried it again. i hit the reset button about 6-7l times in a row and now im typing on the keyboard again. but the F light still does not light up. but the mouse and keyboard are both work now though