After trying all suggestions I am giving up. And here a new finding. If I ever load a new page at least once and correct the fonts by hitting Ctl-++, then, even if I delete all history, including cache, cookies, etc., and go to that website/page again it loads with the desired fonts. So, as it goes now the problem seems to cure itself. A bit boring way but it goes better.
What bothers me is, as I said, it happened all at a sudden. I am absolutely positive I was not mixing with any Firefox settings before I started experiencing it. And as I said I use the same Firefox on my desktop also, were I have no problem what's ever. I guess I hit some weird Firefox or one of his addons bug and I don't even have a clue how to reproduce it. Thanks guys.
