[kahljorn]

umm...

Alright... well. one thing I'd do is try reinstalling/updating all the "Drivers" (i dont think MOST monitors/speakers have actual drivers that you need, though. i usually just plug mine in) or let it do a redetection of your monitor. Try deleting all the information pertaining to the old ones. Did the speakers hook up weird, or did they just go into the standard ports? The next thing I'd do is try plug in your old monitor and see if it freezes. Do the same with the speakers.
Really, something like this shouldn't even be an issue with the monitor ;/ it could be a driver issue... and it could be the monitor i guess if the pins or something that hooks up to the computer are fucked up, but that's a long shot. That's why you should do an experiment with the old monitor after you try the driver/detection thing, though. Your experiment should consist of experimenting with both the monitors and the speakers/headphones. Try them by themselves. Try them mixed and matched.
There's a chance if someone gave you their old monitor there was a problem with it I guess, but it seems strange to me that a monitor would cause lock up :O seems like an internal issue, which is why I suspect it may be some type of driver/detection issues. In the off chance though, do the experiment.