A prohibitory symbol Is showing up on my screen how do I troubleshoot it

The spinning glide says you are running Internet Recovery.

That is an alert [Triangle] symbol, not a prohibitory [Circle with a Slash] symbol.

In Internet Recovery, these low negative thousands error messages indicate that your provided Wi-Fi Network is inadequate in some fashion, and cannot be used (for this purpose) in its current state. We have seen -1000 to -6000 reported, often with a letter appended.

Common problems include:

Hidden Network-name

required use of a proxy server to get Internet access

required use of a login page to get Internet access

Use of a login server or certificate to get Internet access

Use of PPPoE in the Mac to get Internet access (typically only applies to DSL)

Use of Fixed IP address rather than good old DHCP

Variance of the time by more than five minutes

Failure of Router to provide workable DNS server addresses, or providing 0.0.0.0 [may produce -2002f]

If you have an Ethernet port, you may in some cases be able to move your Mac close to the Router and connect to the Router using Ethernet.

The higher the number, the more obscure the problem.

If your battery was completely depleted, the Date&Time could have reverted to the default, which will not work. There is a terminal command to reset to current Internet Date&Time -- post back for assistance.

"A prohibitory symbol Is showing up on my screen how do I troubleshoot it: when I pressed the command and R keys this is what prompted what do I do to fix this"

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Thank you for the second screenshot.

Troubleshooting a Mac Having a Circle with a Link Through it:

I. Start Here: If your Mac Starts Up to a Circle with a Line Through it - Apple Support

II. If No success?...

A. Hard drive Failure, Perhaps:

Your hard drive is likely failing. So try the following:

Run First Aid:

1. Boot: in Recovery Mode
2. Select: Disk Utility
3. Select: Your Internal Drive
4. Click: First Aid button

B. Restore or Install Anew:

• Reinstalling the macOS:

Go Here: How to Reinstall macOS from macOS Recovery - Apple Support

Did you ever, create a Time Machine backup of your Mac prior this this? If so restore your Mac from it. If not, then take this as a learning experience, knowing to always create a backup of your Mac, prior to making any major changes to it (i.e. new installs).

• Installing the macOS Anew:

See if this Site Helps: How to Reinstall the macOS Anew - No TMB Prior to Upgrade - User Tip. Format the hard drive with the applicable macOS, on step D.

In Depth:

Pretty much, it is a matter of:

1. Erasing: and formatting your hard drive to APFS
2. Installing: [the applicable macOS] via a USB Bootable Installer
3. Restoring: info from a Time Machine Backup, using Migration Assistant

Here is the meaning of that screen and what to do:

If your Mac doesn't start up all the way - Apple Support

The circle with a line [Prohibitory symbol] says, "While booting from the specified boot drive, which appeared to be bootable, a Major component required early in the boot process was found to be damaged, wrong version, or missing entirely."

Again, check the link I provided above. That page and symbol are explained.