If you're still getting erratic behavior, power off the other set and test.
How easy is it, or is it possible at all, to hack into a wireless keyboard signal? I have two sets of wireless keyboard/mouse on two different pc's and erratic behavior on one of them brought up the issue. The pointer started to move on it's own, so I checked to see if it might be interferance from the other set, but it wasn't being used, and they're different brands. So considering I do a lot of online banking, it troubles me that it might be possible to hack into the signal, if you're close enough. The devices are rated for up to 20ft, and I do have neighbors that might be close enough. So is it possible to have something like keyloggers to intersect the signal?