Q: Please help, new Mac is being troublesome

I finally got a new Mac because my 8 year old OS wouldn't update to any browsers and the only thing that worked was my Lightroom program for photo editing.  My new Mac computer won't let me print to my HP 3845 printer, shows error "Filter fail" despite being able to test print a page, it won't open "About this Mac" when I click on the Apple Icon and then "About This Mac" or let me open "System Profiler" in the Application folder.  I have checked the Apple Store for updates and restarted multiple times with no changes to any of these areas.  I have also logged in under other users and this hasn't improved things either.  I have a USB connected HP 3845 and DS Mobilie 600 scanner plugged in as well as a USB connected back up. I don't know what OS I am on, my husband set it up and didn't let me know anything.