When I first updated from my old wired keyboard to a Microsoft Wireless Desktop Elite I experienced a problem where random keys would seem to “stick” and I’d get an unwanted string of repeated characters across the screen.

The problem, it turns out, was having my Key Repeat Delay set too short. Due to my impatient nature I would always turn this to the shortest setting so I wouldn’t have to wait if I wanted a string of repeated keys.
To fix the issue, open up Control Panel (Start -> Control Panel) and open the Keyboard item (Select “Classic View” in the left bar if you have trouble finding it). In the dialog that opens, select the “Speed” tab and move the Repeat Delay slider one notch closer to “Long”. Refer to the following screenshot of the dialog.

I’m really not sure of why having this set short causes keys to get “stuck”. I guess that due to the nature of wireless, some interference may distort the signal and tell the OS that the key has been held down longer than it has. Making the delay a little longer will have it wait out this corrupt signal before leaving a string of characters across the screen.