Bleg for Help with Wavy Monitor:

My home computer setup has a Samsung SyncMaster 213T LCD monitor. For no reason that I can discern, a couple of days ago I started to get pretty major "wavy" interference on the monitor. I unplugged it and hooked it up to my wife's computer, on a desk a few feet away, and it worked fine, which I suppose must mean that the monitor is okay, but something nearby is causing the problem. I moved it back to my desk, and promptly got the waves again. I haven't moved any electronics around lately that I can remember. Any ideas? Thanks.