Installing xubuntu 606

[napa at it-np.de]

Hello,

my system is currently running with ubuntu 5.10. 

I'm trying to upgrade to xubuntu 606 because the machine ist to small for gnome. The download of the file xubuntu-6.06.1-alternate-i386.iso is burned on  cd-rom. 

Upgrade via the upgrade manager does not work as it does not recognize the disk.

So I tried a complete new installation by rebooting with the disk inserted. But the the system (IBM Aptiva Intel Pentium III, 256 MB, 10GB HD, Floppy Drive, CD-ROM) does not boot the CD. It always boots the Version 5.10. Copying the sbm.bin file to the  
floppy disk did not work as well (the system does not recognize the floppy drive. So i mounted it manually by using sudo an copied it the same way)

However rebooting the System with a Slackware iso-image works.

What am I doing wrong?

1) Has the the iso-image to be changed before burning it to disk?
2) How can the floppy drive used properly under ubuntu?
3) Has the BIOS to be changed (but why does Slackware boot without change)?
4) Is there any shortut for installing and using xfce under 5.10

Best wishes for the next year.

Norbert