Look Ma, i fixed a mac.  Yes Mac's do break too eventually.  This one needed a new hard drive installed in it to bring it back to life since it was taking 15 minutes just to boot up.. thats a bad sign.  Hope you have a backup.  No problem.  We can do that. 
It is a little challenging for most amateurs to open up an Imac and do basic things like changing a hard drive or a dvd drive or Ram.  Its all under the hood though.  First i removed the bottom four screws, removing a metal plate.  Then i had to find some special Torque Screwdriver bits to open the "special" screws and with a little more effort and some proprietary secrets, i was able to break this thing open and replace the hard drive.  Then i put it all back together again.  Yeah.   The next part involves the customer having the correct DVD's to install the MAC OSX operating system.  Hmmm, similair to installing Windows operating system.  But, before that is possible you have to figure out how to open the CDROM to start the install.  After all that, you have to partition the hard drive to work with the Mac. No more free hints.   Anyway, its difficulty level is about 8 out of 10 if you are not familiar with doing this type of work.  We don't do a lot of Mac work, but we have enough experience to do almost any project involving hardware and software, even a Mac. 

If you need help with this type of project and you are not computer literate enough or dont feel like the challenge, please bring it in and ask for Jim.  I will be happy to help you out and probably be a lot cheaper than the Mac Store if they even do that type of work on an older model like this.   Most places would just tell you to buy a new one..  You dont always have to replace it if it can be fixed. Thanks for reading.