I know how difficult it is to have a function not properly working the way it used to before, @lilavalv. I'll share additional steps to help you set up your payroll in QuickBooks Desktop (QBDT).

To start, let's make sure that your QBDT program is updated to the latest release to ensure you have the recent components and fixes as well as your payroll tax tables. 

Once done, attempt to set up your payroll again. 

If the issue persists, I highly recommend getting in touch with our Technical support team again. I know that you've already contacted them, however, they are the only ones who use specific tools to further check your account and verify the cause of why you're unable to open the forms and set up your payroll. 

I've added this helpful resource that you can access for additional troubleshooting steps when fixing payroll issues: Fix error codes 00000 XXXXX in payroll setup.

We're always open 24/7 if you have any other questions about setting up your payroll, please don't hesitate to leave a reply below. I'm always here ready to lend a hand. Have a good day.