Hello there, @IMAD1. I'd like to impart details on how you can complete the reinstallation of your QuickBooks Desktop (QBDT) software.
To ensure you can log in to your account, please make sure you are the primary admin of the company file. Also, you'll need to exit multi-user mode to finish the reinstallation of QBDT in single-user mode.
Moreover, please know that your access to QBDT online and Payroll Services, Online Backup, Online Banking, live technical support, and other services provided by the QBDT 2018 software are already discontinued. This also means you won't receive critical security updates.
To learn more about our service discontinuation policy, kindly refer to this article: QuickBooks Desktop service discontinuation policy. This includes frequently asked questions about this policy.
On the other hand, here are some of our helpful articles that you can read more about upgrading QBDT to a newer version:
If there is anything else I can do for you about reinstalling your QBDT, please don't hesitate to add details below. I'll be there to help. Stay safe.