Please help, mac won't turn on, tried everything!

Have you tried to 'Safe Boot' - start up holding down the shift key, until a progress shows. Ok to stop holding the shift key when the progress bar appears. If it boots restart normally from the Apple menu.

Have you tried booting with the grey install CD/DVD that came with the Mac? Disk in optical drive and restart holding down the 'c' key - hopefully it'll boot. If it does, at the 'choose your language' screen, make your choice. At the next screen from the Menu bar select 'Utilities' and then Disk Utility. In the window that appears click on the disk at the top of the list (disk manufacturers disk ID) and check that the S.M.A.R.T status is verified. Click on Macintosh HD and select verify disk - if it comes up with any errors select 'repair disk'. If you get any fixed errors repeat 'repair disk' until you get a clean pass. Restart normally from the Apple menu.

It sounds like you don't have a back up of all your files - get a back up drive, firewire or USB, as you are in danger of losing your data. You can backup using Time Machine (if your OS supports - you don't say what version of OS X you are running) or by making a clone of your HD using SuperDuper! or CarbonCopyCloner.

Pity - unless someone else chips in with some other ideas it's looking like a trip to Apple/AASP for repairs.

Hopefully it'll get fixed without losing your data.

When I had a similar situation, it turned out to be a dead hard drive.

Paul's suggestion above is the method I used to sort it out.

If you are unable to boot from the DVD disc, then it's something else.

Even bad memory can cause this situation.

If there is fan noise, it's not the power cord.

Obviously there's a risk but maybe it's not the hard drive but some other component. I'd explain your concerns to whoever you get to fix it and try to get them to do a backup of the drive for you, or give you the drive which you could try putting in and enclosure to milk the data off it, unless it turns out it is the drive that's hosed.

All drives will fail eventually, sometimes after several years but it can happen at any time. Some drives die as soon as the computer is switched on for the first time.

I'm sure you don't want to hear it but back-up drives are cheap and essential.

Eventually, we all learn this, don't we.....

Yeh, it's a hard lesson 😟

Hey there... letterally the exact same thing that you have described has just happened to my intel based mac?... what was the outcome of your problem?...

regards J