Ron P wrote:
I have in my home a Microsoft wireless keyboard which uses 3 AA
batteries. It transmits to a nearby receiver which is connected to a
USB port on the computer. When the keyboard was new, the batteries
would last for 7 or 8 months. For some strange reason, I'm now
changing them monthly.
Recently, I was away for a week and the system was completely shut
down. When I returned and booted up, the keyboard was lifeless. I
tested the batteries, and they tested completely and totally drained
on my meter. That's unusual, because they usually test just weak when
I replace them. So, while I was gone and the system was off,
something drained the batteries completely.

At first, I assumed it was the keyboard, so I replaced it with
another one of the same model, an older one that I still had on hand.
Same result, one month. Does this make sense to anyone? Thanks.

Rig a milliamp meter between the battery and the keyboard. See what's going
on.