After a hd install I installed synaptic and then did an upgrade of all packages. I chose the default (n) "keep old" whenever prompted that a file had been configured by a script. Now when I reboot I get to the Welcome To Linux at Knoppix login screen (in English now) but cannot login. My previous root password does not work and my previous user name does not appear in the menu (just Knopix- Knoppix User and Root).

What did I do wrong and how can I fix it?

Thanks.