There is a way to re sync. I just did it after advice from MS Support.
- Power off your computer.
- Remove the transmitter and the batteries from the mouse and keyboard.
- Power on your computer.
- After the system boots plug in the transmitter.
- Put batteries back in the keyboard and the mouse, the devices will automatically re sync with the transmitter.
It worked perfectly after 3 months of trying to get my keyboard to re sync. I had gone to a PS/2 keyboard and was about to buy another brand.
Finally, I found someone in tech support who knows what they are talking about.
Good Luck, All