2001 Saturn SL1 Saturn SL1 Cluch Pedal puzzle

This car has been a tow car before we bought it. My boyfriend was driving it down the road and then all of a sudden the clutch pedal just stops working. The clutch won't engage or disengage when it is on but when we had it in gear then turned it on it would go. But when going we can't shift out of gear. My dad replaced the clutch him self a couple years ago and a few months ago we had to take it in because there was a clip on the clutch that broke off. We are completely puzzled on what could cause the clutch pedal to just stop.