How can I remove a wrong package? And ethernet is not working on IBM Z60t

[Cromwell]

I installed 10.4.9 on an IBM Thinkpad Z60t. It booted and everything worked fine and perfectly, except for the ethernet card. (That is another questions: How can I get it working?)

 

But what is more important, after I installed a package, the OS X always wants me to restart the computer.

I think I installed a wrong package. In verbose mode one of the last things on the screen was about something with ACPI and speedstep. One of the last packages I installed was indeed the intel speedstep package.

So my question is: How can I remove an installed package? I think I have to boot from the DVD, enter the console and then I have to enter some commands... But which... ^^

 

Thx in advance, Crom