A couple of problems. When installing it over the previous 1.3.6 the configure step during setup fails and lyx has to be closed and opended again to configure. Doing it this way gives completely unreadable fonts in all the dialogs - looks likes 'Algerian' font. The fonts on the menu bars is also a very bold font.
Removing the old lyx dir and installing fresh: Once again configure failed. and Lyx wouldn't even start this time - textclass.lst not found. Going back to 1.3.6... Copied the new qt-mt3.dll to lyx 1.3.6 and got the same font issues. At least reconfigure seems to work. Regards, Johann