I installed a second distro on an already double boot partioned computer. I did not bother to erase the previous distro partition, betting that the new installation would overwrite on the partition used by the first distro. But the second distro did not do that. I think it partitioned the partition for windows in order to make some place to it. As far as I can tell, the first distro remained installed on dev/hda2 (windows is on hda1; I have two swap, hda 7 and 9; three data; one devpts; one systfs; and others) – it occupies 10 Gb of my 20Gb, and it is of type “extended”. It is not mounted.
Now, I cannot access to this partition in order to check what’s in there: And I don’t know how to boot from it.
I guess the best solution is just to delete this partition, and then to impart it to my other partitions. But when I begin to do that, via the “Expert Partitioner”, it tells me:
I chose Cancel. But I don’t know either how to unmount the partitions of the extended partion “Expert Partioner” is talking about. It does not even tell where they are mounted.
I cannot either resize it.

Please help me recover these 10 Gb without spoiling it all.
And once I have these 10 Gb free, where shall I distribute them?

Hm, are you sure to have understood the difference between an extended and a primary partition? As far as I know it is not possible to mount an extended partition, but it is a container for logical partitions -- you can mount, format etc. these logical partitions. Deleting the container (extended) means deleting the contained (logical) as well.

Maybe you should provide the output of "fdisk -l" to give the details of your partitioning.

If you have valuable data on there do not play with the partitions unless you know exactly what you are doing! No more betting!

If your old distro is on /dev/hda2 and you are running your new distro then (as root)

# mount /dev/hda2 /mnt

should make your old distro files appear in /mnt (check you have a /mnt directory first). They will disappear on reboot but you can just mount the partition again.

Otherwise if you want more advice the suggestion to post 'fdisk -l' output is good (you need to be root). Maybe also output of 'df -T' and 'cat /etc/fstab'.

Thanks a lot.
I had understood that extended partition meant a set of partitions, but I did not understood that the set was listed below. So hda 5 to 10 are parts of hda 2. fdisk – l made me understood that because it shows which blocks belong to which partition. Shame on me: I could have realized that by just adding properly the memory so as to obtain the capacity of my hardware.
So in the end it does seem that I have erased my older distro installation (but not my Windows partition) just by installing a new distro.
Yet, there is something I still do not understand: why do I have three partitions mounted on /data1, /data2, /data3 using respectively 1.4 , 1 and 3GB, but that have nothing inside? While KdiskFree tells me that there have no free space and have a N/A size? They are of type ‘Linux native’.

Maybe you created the three partitions but didn't format them? If you used a tool like fdisk or cfdisk to create them, the formatting is NOT done automatically.

If you would have to format them, this works with the mkfs command. For example:
mkfs -t ext2 /dev/hda6
mkfs -t ext3 /dev/hda6
mkfs -t reiserfs /dev/hda6

Thanks a lot. The geeks to newbies communication makes it really worthwhile to switch to linux.

I tried formatting data1 as you suggested. It seemed to work but did not change things a lot - as far as I can see. I still cannot save a file on data1, and its available space is still not recorded in KdiskFree.
I plead not guilty: I really think I did not create these partitions myself. The question is what are those partitions for? Can't I just delete them?

Have you mounted this partition read-writable or just read-only? I don't know KdiscFree and don't have it installed, so can't say anything about that. You can post your /etc/fstab or the output of "mount" if you mounted your partition without an fstab entry.

Also post the output of 'fdisk -l' so we can clearly see how the disk is partitioned.