Much will depend on what is actually wrong with it - diagnosis is always the best approach at the outset.
You first have to develop a simple description of the problem - sometimes called a Trouble Statement - what is wrong with what? What is not happening that should be happening or perhaps what is happening that should not be happening? From this you then develop a hypothesis about the probable cause(s) and then test your theory - little by little you will discover the problem and then be able to correct it.
A domestic appliance repair specialist will be able to do this for you at a cost - find one in Yellow Pages either in the book or On-line.
At least you have the cooker hood in an appropriate room.
Good luck...
Peccavi, October 2009
