Windows not infrequently will damage the mbr, which could cause this problem.

However, you are using a very old version of Knoppix and you don't say what type of hard disk it is. But you hint that it might be SATA rather than normal IDE. If that's the case I would try a newer version. If it's an IDE drive them your version should be fine.

To try to repair the MBR and recover lost partitions, look at the gpard and testdisk commands. Read the man page for each, enter man gpart or man testdisk at a command prompt.