Explain this:

INstalling debian at a friends pc. Started with the net installer and re-partitioned the drive completely. INstalled but made an error so started over. Formated alle the partitions (apparently not) and installed the base
After that did a apt-get install xserver-xfree86 kde kdm
INstalled fine but when doing a startx I get a screen showing the old Fedora screen and then crashing (I needed to install xwindow-system and xwindow-system-core) it worked.
Question is: why is Fedora showing? I thought I formated the drive (twice and sure I did it right) so is the format option in Debian installer 3 not working?

Extra: Just noticed that I can enter KDE now but still Fedora is showing before entering KDE...this is weird

Did you retain an old /home partition. If you did that may be the reason since the settings would be retained in .kde

No, did not retain anything. He used a driver with only one partition so I created a small boot partition and partitions for /, /usr, /swap and /home. Since I made an error I started over with the same partitions and formated them again. Even more strange, the one big partition was ext3 and I went for XFS for all partitions except boot (ext2). After installing the partitions show in size and as XFS so that went well. I just don't understand where that flash of Fedora just before entering KDM is comming from...

After installing a new kernel (2.6.11) and some more software it's gone btw. Still weird that it kept showing after a complete HDD setup change.

Don't forget that formating does not wipe the drive but merely "marks" the drive for housekeeping purposes. Previous data is still present on the drive and will be over-written as the drive fills. Perhaps by coincidence the previous kde data was in the same area and now you have filled the drive with more data the problem has been resolved.