Hi!
More information is required about the KVM--is it PS/2 or USB?
A USB KVM will probably require drivers (which are probably built into
Windows) before it can work. Windows XP works with USB keyboards and
mice, but the support is a little half-baked. Sometimes the devices
just aren't recognized. I find that if anything can prod it into
working, letting the computer start up and then unplugging the USB
cables and moving them to another port will usually prod Windows into
noticing the new devices.
Of course (grumble, grumble, grumble, mumble) this wouldn't be a
problem if PCs still had PS/2 ports on them all the time. I find it
hard to fault them for being "legacy hardware" when they Just Work and
nearly all LPCIOs still include the logic for them.
It's quite possible that your KVM just doesn't work. There is a lot of
poor quality crud (this is me being charitable) out there that just
does not work. If you want a KVM that really works, I highly recommend
the Raritan products. You can find used ones cheap. I bought one with
cables for $0.99. It is from the early 90s, but I've used it with a
USB to PS/2 adapter (for those blasted systems whose designers felt
dedicated keyboard and mouse ports were way too retro) and it works.
Rose Electronics and Cybex (now Avocent) also have good KVM products.
They're not cheap, but I believe you get what you pay for with these
things.
William