Depends if you have a "wet clutch", if so it may be that the friction plates may be just stuck togeather usually if the bike has been sitting for a while. First try warming up the bike, turn off, put into second gear, then rock the bike back and forth and see if the clutch releases. If not you can try parking on a hill, put in 1st gear,hold clutch in,press starter while sitting in riding position ("jump start"), be carefull