Let me give a bit of background on this one.
I ordered an external hard drive from newegg.com and have had it replaced a few times.

Eventually the hard drive gave out (i.e. thrown across the room) and I had to get a new one.
I went out and got a new hard drive, just the external. I used the same case as the first hard drive.

My question is:

Will the hard drive stop working if the fan on the board stops working?

I think I already know the answer, but I just want to make sure before I go and buy a new case.

Thanks in advance

HDDs are subject to over heating hence the fan, I would suggest replacing it... that is unless you are going to throw that one across the room as well.