"Installationsprogrmmet kan ikke formatere partitionen."

Which Windows are you trying to install?
You may have to format the drive by using a bootfloppy instead.
You could try to kill the disk with Killdisk before installing.
www.killdisk.com , it can be found on www.UltimatebootCD.com too.

WinXp and I have a bootable floppy, I vill try the other sugestion tomorrow.
My kid just woke up.

OK, then return tomorrow if you are still having problems.

Filled with virus, leaves the possibility that the bootsector has a virus and is therefore blocking the installation's attempt to format the partition.

If this is a fat32 partition:
Boot on a windows 98 bootdisk and run the following command:
fdisk /mbr
and
format c: /s
This ensure's that the c: drive and bootsector is clean, and you should now be able to continue the installation without having to format from the installation-program.

If this is an ntfs partition:
Do the same as described above, but leave out the "format c: /s" and instead format the partition from inside the installation.

Fromsej the program that you pointet out worked great. Sorry it took me so long to
answere! Just wanted to say thank you for spending you time helping people like me
with there pc problems, please send "svar" so I can give you your points.

Tonnybrandt I didnt have to try it the way you pointed out, but thank you for your sugestion.

I am glad it worked,so here is my answer. ;o)