Microsoft USB Keyboard Stops Responding Randomly?

Since I'm running Windows 7 I thought I'd try to solve this on this forum, although the problem has plagued me all through vista as well but perhaps not nearly as much as it does now in 7.I have a Microsoft 4000 usb (wired) ergonomic "Natural" keyboard. I'll be on a forum typing up something (or in notepad, or anyplace I could possibly type) and all of a sudden the keyboard will stop responding to any key strokes. The only way to get it back to life is to logout and log back in, then the keyboard is working fine (unplugging it from the usb port works as well, although logging out and in is easier for me).When this happens, everything else on the computer is working perfectly fine, the mouse, display etc. It's just the keyboard that basically becomes totally inop. It doesn't matter what key I press they don't respond.

It's not a matter of an older keyboard that the wires might have broken or anything like that as this is a brand new keyboard. I've been using these MS 4000 keyboards for a few years now and have to replace them every year or less due to them wearing out from my fast and excessive typing but it doesn't matter, new or old, at some point, sometimes multiple times per day the keyboard stops responding on me.Any clues as to what might be causing this and more importantly how to prevent it from happening any further?