I had my main internal hard drive dual booting with Linux/Windows. I used Partition Magic to repartition an external hard drive (I definitely didn't say to do anything to my internal hard drive). The external hard drive had an NTFS partition and an ext3 partition. I used Partition Magic to repartition it into one NTFS partition. When I rebooted the computer after the patitioning, the Linux partition on the internal drive was hosed, and now the system won't even boot.

I used Knoppix to boot up the system and ran QTParted. It says the Linux partition on the internal hard drive is of unknown type. My question is, is there any way to recover this Linux partition? Maybe could I just somehow set the type back to ext3 without reformatting it and the data might still be there, or am I screwed? Thanks for any help!

As a rule never trust a Windows software on your Linux partitions because it is beyond its ability.

The partition table can be repaired if you remember the partition type which should be 83 for Linux and 82 for a swap. The filing system will automatically restore itself and there is no need to do any repair.

The most single important point is the relative sizes of you partitions. You are safe as long as there is no error in the size. Even if there is error in the size you can delete all the partitions and recreate them according to the original sizes. A reboot will bring all of them back to you. The partition table damage has nothing to do with the data in the partition interior. You only inflict damages when the partition table is erroneous but you still proceed to write a lot of data on it.

My hda and hdc have 60 and 54 partitions respectively. I have rebuilt them over half dozen times (by deleteing all partition entries and recreating the original size) losing no more than 2 to 3 partitions in total.

I standardise in 5Gb per partition so it is easy to rebuild the whole disk. Think two of my re-biulds were gifts from Partition Magic.