Mac only boots in Safe Mode

Here is my system:

iMac 3.5 GHz Intel Core i5
8 GB 1600 MHz DDR3
AMD Radeon R9 M290X 2048MB
Running El Capitan 10.11.5


So I restarted my Mac like I do every few days to a week and I got a black screen with only the pointer arrow on it. I then restarted in Safe Mode and started reading up on what to do next. The Apple site said to try and restart in normal mode. Did that but got the black screen again.

Anybody have suggestions on what to do? I am not computer savvy so I need things explained to me like I'm 90 years old (I'm not).

(BTW, I did have an issue a few months ago where I couldn't back up the files to an external hard drive and when I took it to a Genius bar, they explained that my computer had 2 hard drives and one I was locked out of for some reason. They had to wipe the computer and I had to reinstall everything from a backup. I hope I don't have to do this again.)

Update:

Unplugged everything for 90 minutes. Hooked it all back up and restarted normally.

You effectively did a SMC (System Management Controller) reset when you unplugged the iMac and let it sit for awhile. Always good to try that - even if you didn't know you were doing it. ;D