Have you checked your firewall isn't blocking it? Failing that I would consider PCAnywhere. We use something in work that does the same thing (useful for monitoring mux's on a remote PC and you can't be bothered walking to the other side of the building or if on customer site). Think it's called VNC. But I haven't used it in a while as I had a new PC (and I'm on holiday currently), so can't remember exactly. Failing that I remember seing some code on planet source code for VB6 that basically did the same thing. Essentially allowed you to control another PC, and see the details in a window. Pretty cool, but note that these things (not just the VB code, but all the remote programs) don't normally run very fast, and usually reduce the colour to something very low (eg 256). This is mainly because all it really is doing is grabbing the whole screen and shoving it back to you. So the lower the colours, the smaller the image files. Of course it depends on connection speeds (LAN would be a lot better), but I can't see you playing Doom 3 remotely. Not using that method anyhows.
KVM switches are normally if the computers are really close to each other. ie. in the same room. I have one with my two older test computers. Basically it allows you to switch between two machines which share the same peripherals (screen, keyboard, mouse etc). It's a lot better as you are actually using the machines rather than interacting with them remotely. These days they also normally come with keyboard shortcuts to flip between machines as well as hardware buttons. Mine is only for 2 machines, but a guy in work has one with 6. Look around though, as I found they cost a load of cash for what they are. Luckily you can get some cheaper ones. Think mine was a Dabs value one, and as long as you kept to 2 PC's and didn't have hardware buttons (all controlled via the keyboard), then was pretty good value.
Cheers
I am 99% probably lying in bed right now... so don't blame me for crappy typing
