computer frustration

[serenissima]

My brother, having recently bought himself an iBook, has come to the conclusion that he doesn't really need his desktop system anymore, so he's letting me have it. I brought home his flat panel monitor last Sunday and hooked it up to my computer last night. It looks great -- but suddenly my computer doesn't recognize my modem. Tonight I tried using my old monitor with the slightly vase-shaped display, but no matter how many times I reinstall the modem, showing the stubborn piece of silicon my drivers CD, it doesn't work.

I don't understand why a monitor could possibly conflict with a modem. I refuse to go out and buy a new modem... and I'm having second thoughts about swapping around the hard drives when my brother's "old" computer arrives at the house.