Hope I'm in the right forum.
My iMac (3.06 GHz Intel i3) has been making a very strange noise. It seems to be coming from the right lower side. It's a steady pop,pop,pop. I have to force quit the imac to stop it. It actually woke us up last night, took me a minute to figure it was the computer.
I've brought it in to a Mac store, they kept it over night and not once did it happen. Before I bring it in again, I was wondering if anyone else has had this problem.
When it first started happening it was more of a crackling sound, but the sounds seems different now.
If anyone can offer some help, I would appreciate it.

Thanks,
Deb