I have a laptop with windows XP and I've tried to dual boot linux. It didn't work out with ubuntu (xubuntu, fluxbuntu). I got it installed and possible to boot but I don't get to the graphical user interface. I tried both the live CD and the hard installation. Instead I tried PClinuxOS 2007 and it worked fine to make partitions and install. It looks like this:

/dev/hda1 1 1 472+ 83 Linux
/dev/hda2 * 16 40657 20482875 7 HPFS/NTFS
Partition 2 does not end on cylinder boundary.
/dev/hda3 40657 77520 18579172+ 5 Extended
Partition 3 does not end on cylinder boundary.
/dev/hda5 40657 56897 8185086 83 Linux
/dev/hda6 56897 61997 2570368+ 82 Linux swap / Solaris
/dev/hda7 61997 77520 7823623+ 83 Linux

I don't understand where I have the installation of Ubuntu. At least it's not hda 5-7. It was done by PClinuxOS 2007. I wan't to delete my Ubuntu and PClinuxOS 2007 also and then try to reinstall ubunutu. I haven't really understood partitioning, though tried and read some to learn. Maybe someone can help me to understand more of the partitioning process.

First, let's translate what you have:
hda1 470K Linux
hda2 20GB Windows NTFS, marked as bootable
hda3 extended (container for the following)
hda5 8.2G Linux
hda6 2.5G Linux swap
hda7 7.8G Linux

hda1 is not going to be useful for anything--I'm curious how it got there, but, if Windows is booting, then don't worry about it.

To see who is using what, boot into PCLOS and enter "mount" in a terminal. That tells you where PCLOS is. Then you can mount the other partitions to see what's there. On the other hand, to simply delete stuff and start over, just boot up from the Ubuntu install disk. When you come to the partitioning step, you can simply tell Ubuntu to take---eg---hda5. You can first delete hda3 and higher and then re-create new partitions, but it's not necessary. (Don't delete hda1--there could be a risk of screwing up Windows.)

The standard PC has a partition table in the MBR (1st sector of the HD) with four entries. If you make 4 primary partitions, then that is all you can have on the disk. To get around this, someone invented the "extended partition". This is an entry in one of the 4 slots, and provides the beginning of a linked list to multiple "logical" partitions. With IDE/ATA, the total number is something like 64, and with SATA it is something like 16.
Windows wants to be on the first (primary) partition and it want the boot flag set. Linux does not care about either.

For more info:
http://en.wikipedia.org/wiki/Disk_partitioning

When I tried partioning from windows xp I think it "happened". I'm not that familiar with partitioning, but I did it before from windows, not linux.

This is what I get as info from mount in terminal and I don't understand where PCLOS is but it must be hda 5 or 6 or 7, because the partition tool in PCLOS created it:

/dev/hda5 on / type ext3 (rw,noatime)
none on /proc type proc (rw)
none on /dev/pts type devpts (rw,mode=0620)
none on /proc/bus/usb type usbfs (rw)
/dev/hda1 on /mnt/hda1 type ext2 (rw,nosuid,nodev)
/dev/hda2 on /mnt/win_c type ntfs (ro,nosuid,nodev,nls=utf8,umask=0)
/dev/hda7 on /home type ext3 (rw,noatime)
none on /proc/sys/fs/binfmt_misc type binfmt_misc (rw)

So I should try fdisk from the ubuntu terminal, because it's what I get. No GUI desktop environment/x window.