Automatic Repair Loop from Hell

[sofrustrated77]

PLEASE HELP!!

Older notebook is sending me in an endless Automatic Repair loop. It all started when I was asked to restart, took for EVER then next time I looked it was on the Diagnosing Your PC page. Followed by Preparing Automatic Repair, then the dreaded blue screen of Your Computer Did  Not Start Correctly..

I have googled & googled & read the forums so I know what the next best steps are BUT this thing keeps telling me that my password is incorrect when I try to get into Command Prompt etc. I know for a fact it is, as I can sign in using it on every other device!  Tried changing it, tried using both the old and new passwords, leaving password blank, to no avail. It won’t even let me boot in Safe Mode using Advanced Settings (one of the only things you can do without a password), just sends me backkkkk to the beginning. 
I am seriously freaking out because I’m not tech savvy at ALL, yet somehow I’ve made it this far as a business owner who does their own books. Using Quickbooks Desktop. On this computer. Which I’m now locked out of and payroll is tomorrow. I also live in a small rural area with no help for miles around, any dumbed down advice would be SO appreciated!

[TheOldMan]

Since " I’m not tech savvy at ALL" it will be difficult from here on.  Since you have to do payroll on this PC, I might need to ask if you do regular backups?  I hope so, but if not there may serious trouble ahead.

Waiting on that answer.