Q: I accidentally turned the Bluetooth off on my iMac, then rebooted my computer and now I can't access my computer. Can anyone help??

Did you do a complete power off of the system or a restart?

You should be able to reconnect the wireless devices if you

1. Power off the system
2. Turn off both the keyboard and mouse
3. Power the system on and let it boot

It should begin looking for devises to pair with, turn the keyboard and mouse back on.

This solution posted by Frank works great. And for pretty much any electronics, powering it off and restarting it will fix any small problems.

I used the Screen Share application from a MacBook, you can activate it from Finder just need to be on the same Wireless Network.