If yes, replace the batteries.

Have one nearby. If not, you may be able to get help from Apple on the phone, for a fee.

Can you plug in a new mouse through a USB port and try it?

They are very helpful and there is no fee. I failed to take a loose label off a CD before inserting it in my drive and jammed it up. They took it apart and found the label crumpled up inside. Clearly my fault but they gave me a new drive for free. When I said that it was clearly my fault and I would pay for a new one they said no, we just want you to be happy! They pulled a new one off the shelf for me and I was on my way home!

See if it boots into safe mode.... That's once the Apple logo appears... hold down the shift key immediately.

That has worked for me in the past.
Also check in settings that something didn’t get changed

see if that works.

There are ways you can also boot off an external drive or USB drive, but try that first

If there is important data, hopefully it has been backed up through Time Machine or other mechanism, then if it is a hard drive issue, it is pretty straight forward to restore the system to a new drive

The other obvious suggestion is Google, and worse gets to worse take it in to Apple

If mouse and keypad are wireless it's probably just the batteries. Are they turned on?

n/t

It was the on button on the end of the battery tube on the keyboard.

I see that it seems you've resolved the issue, I just wanted to pop in and say how thankful I am for a group of people who are willing to help others with issues without belittling or mocking anyone. Just helpful posts trying to fix something. I like seeing the good in people and have to remind myself once in awhile that there are many kind people in this world.