Mountain Bike Vector

Broken gear on my mountain bike vector Pacific?
1, 2, 3.4 gears work fine, but 5,6,7 gears do not work. It There seems to be a problem in the cable that controls the timing chain tensioner. When changing speed to 5.6 or 7 cable simply loosen completely. Help please
Sounds as a problem for the limit, if the cable is loose on the front derailleur. There will be a screw marked "H" that determines how far the derailleur moves the wheel. Someone must have thought he was loose and screwed it back in. You want to to be the highest speed, but do not go to the end. http://bicycletutor.com/adjust-rear-derailleur/
MW2: Vector Themal NUKE! Amazing

