Issue resolved after updating to the latest bios.
Hello! We recently purchased a number of Optiplex 3000s and we have found that the included dell branded stock keyboards are unreliable. They just randomly become unresponsive, we can't replicated the issue for any of the users.  All machines are fully patched and updated, and the issue is occuring on all the machines.  We can work around the problem by unplugging/plugging the keyboard or by running device diagnostics but we would like a better long term fix.  Any suggestions appreciated.
Optiplex 3000 Keyboard