If it is an iMac:1. Shut down the computer.2. Unplug the computer's power cord.3. Wait fifteen seconds.4. Attach the computer's power cord.5. Wait five seconds, then press the power button to turn on the computer.6. Press and hold the Command-Option-P-R keys before the gray screen appears.7. Hold the keys down until the computer restarts again at least twice.8. Release the keys.
The letter P and the letter R
Do you have a wireless keyboard or mouse or are they both USB?
OK do you have a USB mouse we can use?
Are either devices functioning ? Mouse or keyboard?
Turn the mouse and keyboard off then back on. Are you sure they both have good batteries?
OK can you borrow a USB mouse so we can use it to re-pair your devices? I could connect by remote but you have to be able to open the file I send you.
Try this with your mouse:
Follow these steps to set up your Magic Mouse 2, Magic Keyboard, or Magic Trackpad 2:Connect the Lightning to USB cable to the Lightning port on the device, and connect the other end of the cable to your Mac.Make sure the device's power switch is in the ON position. (Green will be visible.)The device appears in Bluetooth Preferences and automatically pairs with your Mac.The Bluetooth Preferences window shows the connection status and charge level of your device. When the device is charged, unplug it for wireless use.
The mouse is rechargeable and came with a cable that you plug in to the computer.
OK it should automatically pair when you plug it in to the computer. Try restarting with the mouse plugged in.
IT IS NOT A USB MOUSE but it has a USB cable for charging correct?
The port on the mouse is called a lightning port you plug the cable in there and then in to the computer
I realize that which is why I am explaining it to you did you restart the computer with the charging cable plugged in to the mouse and the computer?
OK and it is still not working? Then you will need to buy a USB mouse to use so we an reconnect the devices. It is always good to have one on hand anyway. They are very cheap: http://www.amazon.com/START-Optical-Lenovo-Laptop-Notebook-Black/dp/B01FSD7Z4C/ref=sr_1_12?ie=UTF8&qid=1464978077&sr=8-12&keywords=usb+mouse
OK good luck let me know.