Hy,
thanx to all.
I do not really understand Grub, but Lilo is transparent even for me

To bring the story to an end:
Install Sidux from Live CD: no problem (installer referred to the partion as sda8 instead hda8 but who cares)
Changing Lilo: no problem
Reboot: Sidux starts booting

Sidux claims file system hda7 (my Vector Home partiton) corrupt, offers to start root console for repair: NOOOOO
Booting goes on
Login starts
Desktop starts (looks nice, KDE is running on my box, AMD 1300+, fast enough)
Lots of entries in the various menus
No network???
netcardconfig tells me: no supported card recognized? (the Live CD did find one)
Summary: failed! I do not need a distribution that wont find standard hardware out of the box
Sidux Live CD for free, only used once. Please call 0049 4153 599489