Never use Partition Magic in a dual boot windows/ Linux

GParted couldn't change a partition on a external hard disk from fat 32 to ext3. So I tried to do do it with Partition Magic. It being a external disk a reboot didn't seem part of the process but it was and it screwed up my system. Unable to boot into Linux. The grub menu was easily restored. But after that error 17, unable to write, read-only file system and x server could not be launched etc. The mount commando was crucial in discovering that the root parttion wouldn't load.

Through WWW it became clear the fault should lie in the fstab; located in ~/etc/fstab , that was indeed totally screwed up.
Important commands in this field:

sudo fdisk -l

sudo blkid

or

ls /dev/disk/by-uuid -alh

Compare the results with the fstab file that you can open with sudo gedit /etc/fstab when you're in the root. This already solved a lot of problems but still it didn't work.
Finally I found the error the defaults options was listed before the filesystem description (ext3) in stead of after... Also I had to recreate the home folder in the right partition (another one as the root partition). So first delete it in root and sudo mkdir /home
and then sudo mount /dev/sda7 /home

The only good thing about all this misery was that I was able to solve it, but damn I 'm gonne deinstall Partition Magic.