If the Apple Store you visited has a Genius bar, call ahead to set an appointment
for their genius or specialist to test or diagnose the computer, in case of failure.
This diagnostic testing is a free service in some locations outside the US/Canada
and does not require an AppleCare plan or warranty to be in effect. Other third-
party or authorized Apple repair service centers may offer testing at a fee rate,
so a Genius bar appointment is a fair value in troubleshooting an issue.
Correctly identifying what build model year and system your computer configuration
is, helps us volunteers try & find more information to answer questions. If your iMac
was made before 2005, it probably is a PowerPC hardware model; if made after,
it likely is an Intel hardware model. There is a difference in troubleshooting as the
system and hardware both changed in the life of the iMac name, several times.
OK, thought you might know without turning the computer on. Try this:
Enter your serial number and it will identify what Apple show for your model. However, please don't post your serial number in an open forum for security reasons.
How to find your serial number:
One reason we need to sort the model is that this forum is for pre-2006 iMacs and they have different troubleshooting schemes than the newer models. Apple's non-intutive labels for the two iMac forums mislead a lot of people with newer Macs to post here instead of the forum for newer (Intel-based) iMacs.