IMAC not starting up after installing

[zfantastic4]

I have an older imac and after installing a mac update I was required to reboot after install.

It froze at the beginning of start up at the apple logo. The spinning icon is the only indication on the screen as if it was working on loading. There is noise from the imac as if it is starting up but nothing happens.

I have let it run hoping it would eventually start. But nothing.

IMAC DV400 is the model number.

Any advice would help

Thanks
Tony

 

[jja]

Have you tried to start it in safemode? When you start the computer and you hear the tone, immediately press and hold the shift key. After you see the apple and the little spinner let it go. See if that works.