My 27'' iMac was delivered less than 20 hours ago and I immediately set to: By this time it was time to get some sleep so I shut down the iMac. and this morning when I tried to start it again i can ...

I've tried the verbose boot mode (hold command-v while booting), safe mode (hold shift), and single user mode (command-s). Nothing. It does not get past the grey screen or show the Apple logo.