Mark Olsen

Hello my GTA single player is not working and i read you have to delete some temporay files and reinstall but the deal is i dont have the disk cause my friend installed SAMP on my pc and said he would crack it so i wouldent need the disk witch he took and he has lost it... I wonna complete single player cause i never got longer the the 5th mission in the first city and now my game dosent work is there a way to fix it without reinstall ? Only SAMP is working. Mark Olsen