When I click sleep, Imac turns off not just sleep

Hi Hank,

Some things to try...

Have you done a PRAM reset, CMD+Option+p+r...

http://support.apple.com/kb/ht1379

In fact, do 3 in a row, takes a bit of time.

Intel-based Macs: Resetting the System Management Controller (SMC)...

http://support.apple.com/kb/HT3964

(SMC reset= Shut down, disconnect power cord for 10 seconds, reconnect power cord, wait 5 more seconds, turn computer back on)

but it is slightly different: (PMU REST = Shut computer down, disconnect power cord for 10+ seconds, reconnect power cord WHILE SIMULTANEOOUSLY PRESSING POWER BUTTON, let off power button for a few seconds, then press power button again to restart the mac mini.)

Can also be caused by USB or Firewire devices.