Quote Originally Posted by rahmuss
.... and I could try to force the mount in Knoppix; but I'm worried it will kill the data. ....
If you want to try to force something, use the mount command and the read-only option (man mount for details), it should not harm anything. But you may very well find that Linux can't mount the partition. Windows is quite capable of destroying partitions that way, I have several drives that it has done it to, even without a one year old.

Even if you can't force a mount, there is a chance that only the partition table is mucked up, not the partition itself. Gpart or testdisk may help you recover in that case, see man gpart and/or man testdisk for details.