Had the same problem - this worked for me ... With Pegasus closed, remove the files state.pmj, cache.pm, desktop.pm0, folstate.pm, hierarch.pm, mailboxp.lck from the PMAIL/MAIL folder (I put them on my desktop just incase I needed/wanted to put them back). (Pegaus will recreate these files when you startup Pegagus.) Start Pegaus and Voila!! The menu buttons/text are restored. I don't think all of these files are the problem, probably just one of them, but I didn't want to take anymore time to figure it out. Hope this helps.

In the 3 window preview view, all of a sudden, the top of the folder list and top of message list have moved up to cut off part of the menue bar.  In text only the text is almost unreadable, and it is hard to click on the menue choice, and difficult to click the column heads to sort the message list.  In text and graphics mode, the graphic are cut off, but at least I can read the text.  How can I get back to normal?

 Thanks

Have you tried to go to "Window" - "Cascade" or "Enlarge" in the menue bar?
Another idea would be to delete the value in the line "Application window rectangle" in pmail.ini

Greetings
Thomas