Help - I have a QB wupport contract but don't know how to get there.

Had a problem with my computer - took it to best buy Geek Squad they had it for a week.  Said they cleaned up all kinds of temp files, fixed up the registry errors and optimized. Now QB doesn't work.  I can open the company but I can't gegt the payroll update to pay employees.  Also can't connect when on the Intuit website.  Can't find my disc - thought I should uuninstall and reinstall. I use QB Premier Pro 2020.  Need help.  Error FCS damage 15242 and unable to connect to online support services. I tried the instructions to repair - get more error codes.  What do I do?  Can't find my license key - where do I look?  Can I download to reinstall?  Help!