If your switch (I assume it's a KVM - Keyboard Video Mouse - switch) is a physical turn-the-know type switch rather than a digital push the button switch, that is a common problem. Furthermore, I found that the keyboard would often go berserk with that kind of switch. I'd suggest trying to use the machine with the switch out of the loop for a while.
Out of curiosity, what do you use the other computer(s) for? Server work? Firewall? A second operating system to tinker with? You may be able to use VNC to access the computer over the network instead of using a KVM (I did this for a while until I found that everything I wanted to do didn't even require a GUI - at which point simple SSH worked fine).
Out of curiosity, what do you use the other computer(s) for? Server work? Firewall? A second operating system to tinker with? You may be able to use VNC to access the computer over the network instead of using a KVM (I did this for a while until I found that everything I wanted to do didn't even require a GUI - at which point simple SSH worked fine).