Stripped screw
 

The cog recently came off my motor as I was trying to undo one of the screws ive stripped the head and because it's in a tight place I can't dremal the head how else can I get this screw out ?

Use the correct size easy-out... you may have to drill to get to the right size. They do make small ones. Search easy-out screw extractor.

You could also drill the head off then remove the remaining with pliers after the motor is out. go slow and easy, again with the right size bit.

left hand drill bit push hard as it bites will screw it right out