Either the switch spring has given way, in the paper feeder tray, or then you have some piece of paper stuck in between the rollers.
Open the top by lifting the Scanner Bed, use the flashlight and check the edges where you see the rollers, look for pieces of scrap paper and remove if visible.
Press the Start Button and see if the rollers move.... keep an eye out for pieces of paper....
Remove the tray,and use a flash light to check. Remove the color cartridges and try to run a test.