Are you sure is the front derailleur and not the left shifter?
Can you hear a click from the shifter when you try to change gear?
If the problem is with the derailleur then you probably need to adjust it. There are a few tutorials on how to do it.... see the tutorial by the bycycletutor.com
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Can you hear a click from the shifter when you try to change gear?
If the problem is with the derailleur then you probably need to adjust it. There are a few tutorials on how to do it.... see the tutorial by the bycycletutor.com