Need help with squeaky window.

[PeteG]

Ever since the heavy rains in New England about 2 weeks ago, my drivers side window squeaks all the way up and all the way down on opening and closing. It's only happening on the driver's window. Unfortunately, my driveway had been under reconstruction when the rains began and I had to keep my X5 parked outside the whole time. I thought it might dry out with time, but it doesn't seem to be going away.

Any idea what's going on? Is the fix a DYI? I'd hate to have to take it to the dealer so he can charge me big bucks to fix asqueaky window.