Lpfix5: Your command worked for active windows only.
Dognach: Yes, I was doing as you said. But it do not work for different PM windows. I mean, if you PM me right now, the window will use Fixedsys as standard font. Then I will have to change it manually. If another member PM me after that, the window will use Fixedsys again. And so on.
deegee: Your command worked successfully (I guess).
Thanks again for saving my ass (it rhymed).