Do a quick search next time.. there are TONS of threads on this topic.
Its the motor, it must be replaced and soon, as it will die and leave you with an open window with no way to close it, and it will usually start to rain.
dont bother with a junk yard motor as the motors on these cars die quickly and you will most likely get a motor on its way out.
New motor is fairly cheap 50-80, but install is a pain. You need to drill out the rivets and replace them.
I got my mechanic to do it for $200.