Currently Being ModeratedApr 21, 2013 10:54 AM (in response to Maries021)
Suggest you take it in to an Apple store.
Noise can come from the fan or from the hard drive. If the latter, worst case scenario, your data could be in danger.
Always a good idea, but really critical now is to have a complete back up of your data.
Currently Being ModeratedApr 21, 2013 11:28 AM (in response to Maries021)
Direct you to the proper forum for MacBook :
MacBook Series Forums
Mac OS X Help
Isolating Issues in Mac OS
Get Help with your Product