The quick way to reset everything is to reinstall the program but in this case, try deleting the files of the program. Go to the folder location below on your computer then delete the Express Accounts folder folders:
C:\ProgramData\NCH Software
C:\Users\(Your computer profile)\AppData\Roaming\NCH Software\Express Accounts\Accounts
If you can't find the AppData folder, set Windows to show hidden files and folders with the steps from this link: https://support.microsoft.com/en-us/help/14201/windows-show-hidden-files.
After deleting the Express Accounts folder, restart your computer then install it again from the next link: