I just bought a 97 Eldorado ETC with 23,000 miles yesterday. Today when I rolled down the drivers side window it stopped half way and would not go up or down. Then I opened and shut the door and it worked again. This happened three times on the way to work. Any quick fixes?

Also, a stability control message flashed on the display. It said I am restricted to 90 mph. Should I worry about it?