IMac 2006 Frequently Shutting Down

Question

Hey! For a while now, my iMac 2006 has been very frequently shutting itself down and then it can sometimes take up to and over and hour for it to turn back on. this started over a year ago and then it went away this past summer but recently it has been doing it a lot. The computer is only running for a short amount of time and it happens when I am using any program (I have tried several). I read somewhere that vacuuming the computer's vents to remove dust helps and I usually do this whenever the computer shuts off but I was wondering if anybody knows what I could do to permanently fix this issue. Here are some of the specs of the computer I am using:
Processor  2.16 GHz Intel Core 2 Duo
Memory  2 GB 533 MHz DDR2 SDRAM
Graphics  ATI Radeon X1600 128 MB
I've also been running OS X 10.7.5 and I am not sure if my computer can handle the new OS X Yosemite
(Not sure if these will help)
Thanks!

Answer 1

Your machine is exhibiting symptoms of a failing HD. Run Apple's Hardware Test in extended mode at least 2-3 times back to back. If errors appear on any pass take it in for repair at an AASP, an Apple Store will not work on it due to it's age. The reason to run the test 2-3 times back to back is AHT does not always  pick up errors on the first or even second pass, however when it does find errors the report is correct.
By the way, your machine will NOT run Yosemite or Mavericks, it's simply too old. The minimum system requirements are:
Yosemite will run on the following Macs:
iMac (Mid-2007 or later)
MacBook (13-inch Aluminum, Late 2008), (13-inch, Early 2009 or later)
MacBook Pro (13-inch, Mid-2009 or later), (15-inch, Mid/Late 2007 or later), (17-inch, Late 2007 or later)
MacBook Air (Late 2008 or later)
Mac Mini (Early 2009 or later)
Mac Pro (Early 2008 or later)
Xserve (Early 2009)