Fan never takes a break

Hey,

Was wondering if someone could help me with something. I have a self built computer thats around 2 years old. Its still a great computer except for one problem that has developed gradually over the past month. out of the 5 fans that are in my computer, there is a 1 inch fan next to the CMOS battery that just doesn't want to go off... I have taken apart and cleaned all but that fan (because its white pegged to the motherboard). So I know it could be due to dust insulating the heat, thus making it over heat... However, I did blow it out and it appears to be clean... Do I need to try to find a new fan for the board or do I need to just buy a new board... it getting to be REAL annoying... sounds like a small car trying to make it up a hill... (surges, I mean)

Thanks for your help,
Robert

 

Mobo model? make? etc..