I have a laptop with a 40gb hdd. I am using a swap and a system partition. I want to change that so I can mount /home on its own partition. That means I will have to resize the root-partition, and I don't want to loose any data. I have free space, just using about 5gb right now.

I have downloaded GNU Parted but it tells me I can't use /dev/hda1 since it is mounted. And the problem is that since I only have one partition (except the swap) I can't use parted unless hda1 is mounted.

And I can't just remove the hdd and put it into another computer since this is a laptop. Do you guys have any suggestions on how to put in another partition on my hdd without having to format it?

if you have a distribution boot/rescue/live disk

boot using that, then you can work on the hda

yes I have a boot disk. But if I boot with that then how can I access any progam to partition with? The only one on the cd is fdisk and cfdisk and IIRC they tend to format the disk when resizing them. I would like something like partition magic where you can change size of partition and still keep the data.

I thought GNU parted did that so I have installed it, but if I boot from a cd how can I access parted without mounting hda1?

You need to find a rescue cd specifically that comes with a partition manager that can resize.

Have you no distro's like Suse?
Maybe download an iso which allows you to boot
into a ramdisk allowing for rescue.
mount your root device, copy the parted to
the / of the ramdisk and run it.

or....

format your swap partition as a filesystem.
copy your home onto it (if big enough)
re-install,
make a bigger home partiton,
copy home to new home,
make it a swap partition again.

no?

Boot using either Knoppix (http://www.knopper.net/knoppix/index-en.html) or INSERT (http://www.inside-security.de/insert_en.html). You'll have QtParted on knoppix or other tools on INSERT.