Wont boot

Have you been booting from an external drive? RE: "I switched it so it booted off if the hard drive with the Mac OS on it" Indicates it wasn't booting from it before.

If so, what caused you to start booting from external? That may help explain what's going on.

Generally, a normal start up takes you to the signing screen. Is /was that not happening and you got a utilities screen? If so, that's likely a problem also.

If you're getting a stalled progress bar: If your Mac starts up to an Apple logo or progress bar - Apple Support

This is a possible fix, but notice the admonition to contact Apple Support if it fails to help.

What does the "I switched .... " comment mean then? Did you have to switch initially because of some problem? If you didn't switch, I completely don't understand what you are saying by using the word "switch"..

For the exclusion image: If your Mac starts up to a circle with a line through it - Apple Support

For the progress bar: If your Mac starts up to an Apple logo or progress bar - Apple Support

Apparently you have both situations: "it boots up to white screen then just the Apple logo then the 🚫symbol then it goes to the Apple logo with the progress bar."

Both problem sites have an admonition to call Apple support if the procedure fails. With what you have going on I suggest you do that first maybe.

You do realize a 2008 Mac is 15 years old and obsolete. It's time you rested the tired old boy and got something newer.