Thanks for your suggestions. No luck yet, here are my findings so far ...
Will launch in Win98, but ...
- sumatra pdf 0.8 tweaked version : compatible with .pdf only
- abode eBookReaderInstall22.exe : compatible with .pdf .htm and .edt only
- cool reader 2 eng : compatible with .doc .htm and .fb2 only
Will not launch in Win98
- docviewer-master : not able to open document with internet explorer 5
- can't get the jar file epublib-tools-viewer-latest.jar to launch with jre-1_5_0_22-windows-i586-p-s.exe
- Python 3.6 will not launch in w98 so no luck with termpub-master
- stduviewer_epub reader W2K
Good trick to unzip the .epub. But sometimes files are html, sometimes xhtml . But they are also split in chapter (or even not by chapter), so not very convenient.
Of course I could too use on a recent computer with calibre and translate from .epub to .lit and use microsoft reader 2.1.1 (small and fast app), but I would like to find a lazy boy solution ...
Win 3.1 : HP Omnibook 425 + Toshiba T2130CT
Win 9x : Dell Latitude Cpx H500GT + Dell GX1
Win XP64 : Asus P5B Xeon