OK I have another newbie question. I purchased a Trek 3900 about 7 months ago. On the second ride the chain snapped. I bought a shimano cn-hg90 chain to replace it that is supposed to be stronger. A few rides after that I managed to strip the peddle off and my bike shop replaced the crank with a "stronger" shimano one. After not riding for awhile I took the bike out for a spin and it would not shift into all the gears. My question is what should I upgrade next? Should I even bother with this bike or should I look for a new iron horse warrior type bike (disc brakes sound cool)? Any thoughts on situation or other bikes are greatly appreciated and I do mild trial riding and am kindda rough on things being that I am 6'2 230. -THANKS-

Thinking off the HARDROCK PRO DISC as well