I had a dual boot XP/RHEL system. I attempted to install kubuntu over the RHEL partition. Somehow, I missed the screen that would allow me to choose a partition or there was a failure in the installer. I don't know how that was possible but it happened.

It started to reformat the drive and I cancelled it.

However, my machine is no longer bootable and there was some priceless information on my windows partition that had not yet been backed up. Is it possible to recover this information?

Any help would be greatly appreciated.

tools available:knoppix cd, windows install cd, kubuntu live cd

Did it repartition the drive and try to format it as one large partition? If so, then you are in pretty bad shape. Knoppix includes TestDisk, which is probably your best shot at recovery.

If the installer just wiped the boot loader and started formatting over RHEL, then things are not so bad as you can simply reinstall GRUB and move on.

You should see pretty quickly which way it went when you boot to Knoppix. View the partitions on the disk with a command like "fdisk -l", and see if there is one partition or multiple ones listed for your HDD.