My iMac won’t turn on, I did almost everything that was told but nothing happened. Please help.

The basic steps:

How to turn your Mac on or off - Apple Support

If your Mac doesn't turn on - Apple Support

Reset the SMC and NVRAM, and try again:

How to reset the SMC of your Mac - Apple Support

Reset NVRAM or PRAM on your Mac - Apple Support

Then try Safe Mode:

How to use safe mode on your Mac - Apple Support

See if the hardware diagnostics report any issues:

How to use Apple Diagnostics on your Mac - Apple Support

Older iMac: How to use Apple Hardware Test on your Mac - Apple Support

If you’re not sure how old the iMac is, to figure out whether to use Diagnostics or Hardware Test:

Identify your iMac model - Apple Support

If you’ve then done “almost everything” and have been unsuccessful, you will want to avail yourself of Apple Support. Use the Contact Support link in the upper right.

Hi, what year is your iMac? Do you have internet? Shut off your iMac. When you turn it on press n hold command+R keep holding till you see world or recovery screen.