Regularly (once per week or two) logging in to POS is required.
If there’s no data in POS database, you can just uninstall and delete c:\woopos folder, and reinstall WooPOS.
If you have data, please move the backup files from c:\woopos\bakcup folder to another folder. Uninstall and delete c:\woopos folder, and reinstall WooPOS. Let us know your email account or database ID on top of POS screen, we will enable restoring backup so you can follow this instruction to restore the backup.