I did a complete uninstall of the HP software, unplugged the printer, cleaned my registry, and rebooted. I went through a complete reinstallation.
I printed a test page (8 x 10) and it worked. Then I loaded a no. 10 envelope (correctly -- I've been using HP printers for over 15 years and know how to load paper and envelopes), set my word processor for a No. 10 envelope, and made sure the return address positions were set for the least distance possible.
Ideally, the return address should be no more than 1 cm from the top and 1 cm from the left.
The same problem occurred. The return address is 1.5 cm from the left and a full 2.0 cm from the top, and looks pretty bad. Is there a solution that will not cause the printer to stop printing altogether?