MTB wont shift into 7 My new MTB wont shift into 7th gear or the smallest cog as some call it.I made sure it was in the 3rd cog on the left side to avoid chain crossing.Also there is a weird noise coming from the chain at the 7th setting on the shifter.

If all other gears are working fine, then probably you should adjust H screw only. If doesn't help, then you should adjust INDEX barrel. See Rear Derailleur Adjustment