Well, Problems are solved... > program > > is waiting for latex run 1. And then LyX gets stuck.
There was obviousely a problem during installation of MikTeX caused by the firewall - after switching the firewall off and a new installation LyX didn't die anymore. But then I also had the following problem: >I get here 4 errors. One is that \Telelfon is already defined: > > \newcommand\Telefon{\mvchr{84}} >Your command was ignored. So I opened marvosym.sty (\MiKTeX 2.5\tex\latex\marvosym)and changed the spelling of "telefon" (I guess I could also just have deleted it) and everything was just fine. Anyway, thanks for the quick response, Axel