Help. How do I fix a prohibitory symbol on iMac?

[aznboi91]

Help. How do I fix a prohibitory symbol on iMac?

I tried restarting the machine and it doesn't work.
I have the wiress trackpad and mouse. Are these able to connect to the iMac with this screen?

Thanks!

 

[Krayzkat]

Can you post a screenshot/pic?

 

[aznboi91]

Can you post a screenshot/pic?

[doublepost=1553623755][/doublepost]Tried resetting PRAM
Tried going into internet recovery mode and it is only showing me OSX Mountain Lion instead of Mojave... Any reason for this?