That is a 1995 Rockhopper. If it has the original cranks, they may be under recall. Just do a Google search for " Shimano crank recall", and check the recalled part numbers against what is stamped on the backsides of your crank arms. If it is one of the recalled cranks, your local bike shop can get a replacement kit from Shimano. The kids will include cranks, bottom bracket, chain, and front derailleur. It's recall that was issued in 1997, but recalls never expire. I've replaced three in th last six months. There was an issue with some crank arms breaking.