Went with a new ISP. Thunderbird was not working right. After spending hours trying to get it to work, backed up as instructed, uninstalled and reinstalled the latest version of Thunderbird. Still have problems but the main issue is not being able to send PDF files or even something scanned from my printer. The error message I keep getting is: "There is no email program associated to perform the requested action. Please install an email program or, if one is already installed, create an association in the Default Programs control panel.". I have gone into Default Programs, associated Thunderbird as my email client. Doesn't work. Went into Regedit and double checked that Thunderbird is my email client. Doesn't work. What do I need to do so that my Windows 10 Home PC, Version 22H2 can send PDF files. All other regular emails (in/out) work fine.