For what its worth...I can't remember the specific year-make-models of iMacs, but its was really easy to find info on youtube with specifics...My mom had an iMac she bough at compUsa and the kid salesperson said 'ya this is an intel' She bought it, the kid was wrong and she ended up with one of the last ppc model imacs... But she started getting wierd things happening after 6-8 months...Fans would start blazing all of a sudden with everything getting 'buggy'...apps not starting, freezing...things just acting like maybe corrupt drivers on this or that...I was advised to do a pram reset, reset the PMU...leavethe machine unplugged for 15-30 minutes (which seemed to work for a while) and all sorts of key combos to use during boot or reboot...clean install of the OS. Nope. Even booting of and external drive didn't seem to improve things after a certain point. Usually hidden OS folders/directorys would show up...Nothing ever fully fixed things. Got it to boot from external and work well enough for my mom to get email and a few simple things...It got to a point where it wasnt worth even trying to get the thing to boot up properly....
Turns out Apple had faulty capacitors on the motherboards in, I forget how many year/releases of the iMac line. When they started to fail, the caps would get hot then cause all sorts of little symptoms to start showing themselves getting worse as the comp heated up. The bad caps were widespread wide enough to make it really easy to find info online. Along with all sorts of info about how to test the caps or try to, hints on attempting very clean desolde+resolder of new caps on the motherboard using silver solder.
I ended up taking the drive out and selling the rest to some guys for scraps basically.
crwdns2934105:0crwdne2934105:0
crwdns2934113:0crwdne2934113:0
crwdns2915270:0crwdne2915270:0
crwdns2889612:0crwdne2889612:0
0
crwdns2942205:01crwdne2942205:0
Apple iMac "Core 2 Duo" 3.06 21.5-Inch (Late 2009) Specs
Identifiers: Late 2009 - MB950LL/A* - iMac10,1 - A1311 - 2308
crwdns2934271:0crwdnd2934271:0 mayer crwdne2934271:0