How many PCs do you have?

Assuming 2, you either need a USB multiplexer (not KVM) or something like keyclone, Multibox, Synergy. Most of these are listed in the stickies, Multiplexer will probably be listed on the hardware board. If its one PC with two screens, you only need something like Keyclone or AHK, to be able to send single key press' to multiple clients.