Computer speed went to about 1/8th of what it should be

From the forum tutorial section I have found you:
Clean Boot - Perform in Windows 10 to Troubleshoot Software Conflicts

- or you could use a search engine...

A clean boot means (roughly)
no user added start-up programs or services

So you can see what Windows is doing without added extras.

via msconfig + start-ups in the task manager.

Note: it can be a good idea to set a restore point (or even back up the registry) before doing this.

To check you have done a clean boot, you should have fewer services running than normal, and any added 3rdparty startups should not be running (e.g. typically you will have nothing in the system tray bar your AV if any, clock, internet connection icon).

Can you see a difference to when you boot normally?

And check here:

- these should be disabled

If you are convinced you have done a clean boot, and there's no change in boot time, you need to examine the difference between what's running in Safe Mode and what's running after a clean boot - or do a technical analysis on your boot time (which is possible but I've never done it, so would need to research it or leave this for someone else to advise).

Note that some drivers are loaded when you do a clean boot which are not loaded in Safe Mode, e.g. graphics, and your internet connection.

For reference (technical)
Analyzing a Slow Boot with Windows Performance Recorder & Analyzer • Helge Klein
4 BootVis Alternatives to Analyze Windows Boot Performance • Raymond.CC