My zoom stopped working on my Microsoft keyboard. Comfort keyboard 4000. Model 1045

SOURCE: Windows vista and Microsoft wireless key board and mouse

here is Microsofts' page for driver downloads. http://www.microsoft.com/hardware/download/download.aspx?category=MK
put in your device model number , operating system, etc.
make sure you download it to your desktop so you can find it
run it to install and follow the prompts

SOURCE: Microsoft wireless comfort keyboard 1.0A problem with games

Wireless keyboards shut down after not detecting changes in input over a time period.
This is usually Hardware related in the keyboard to base station so there is no way to fix it using the particular keyboard.

My recommendation would be to go to a USB corded keyboard which would not have to have the power restrictions that a wireless one does.

Alternately if using a first person shooter, tap the strafe keys while you are running long distances, or in racing tap a unused key to keep the keyboard in alive transmit mode.

SOURCE: Can't type

The keyboard wireless receiver is likely having troubles receiving. Usually due to low power or not in a direct line of sight.