Installing Ubuntu 8.04 on a ThinkPad T40

I try to do install ubuntu 8.04 (hardy version) by installing 5.10 (breezy version) desktop CD, upgrading with apt-get dist-upgrade to 6.06 (dapper version) upgrading with apt-get dist-upgrade to 7.04 (feisty version) The last step doesn't work, worst it breaks my installation, impossible to do administration tasks.

Finally I decide to install the Ubuntu 8.04 desktop CD, everything seems to work out of the box on my laptop.