Hi! I would try running the reconfigure script by hand, as Paul A. Rubin suggests: http://www.mail-archive.com/lyx-users@lists.lyx.org/msg52019.html
If this does not work, you may find some other workarounds here: http://www.mail-archive.com/search?l=lyx-users%40lists.lyx.org&q=LyXTextClassList Nicolás John M. Linebarger wrote:
I just downloaded LyX for Windows 1.4.3-5 and I get this persistent error that makes the program completely unusable. It says that no textclasses are found. So I look at the mailing list archives, which state that I should blow away my Application Data LyX directory and regenerate it. I do so, and it tells me that tex\latex\IEEEtran\IEEEtran.cls is missing and that I should install it. I do so. I get the same error. I go through this several times, on two different machines. Same error. LyX is unusable and I can't even get a menu up so that I can reconfigure it. Any ideas? I'm about to throw my machine against the wall and call it a night ...
