First of all, thanks to everyone for replying!!

To OErjan: I changed fstab and the relevant lines are

/dev/hdc3 / ext3 defaults,errors=remount-ro 0 1

(where the old /home resides), and

/dev/hdc4 /home ext3 defaults 0 0

(where the copy of the old /home resides (made as specified in the HOWTO with

cp -Rp * /mnt/hdc4/

executed as root from the old home directory). In response to your other request, the output of fdisk -l is "Konnte /dev/hdc nicht öffnen" (english: "Could not open /dev/hdc"). I will try your suggestion about creating /home2 etc. shortly and will report the results.