When I enter recommended code I get this: knoppix@Microknoppix:~$ df -h Filesystem Size Used Avail Use% Mounted on rootfs 498M 44K 498M 1% / /dev/sr0 4.0G 4.0G 0 100% /mnt-system tmpfs 2.0G 38M 2.0G 2% /ramdisk /dev/cloop 10G 10G 0 100% /KNOPPIX unionfs 2.0G 38M 2.0G 2% /UNIONFS unionfs 2.0G 38M 2.0G 2% /usr unionfs 2.0G 38M 2.0G 2% /home tmpfs 20M 3.0M 18M 15% /run tmpfs 20M 3.0M 18M 15% /UNIONFS/var/run tmpfs 10M 0 10M 0% /UNIONFS/var/lock tmpfs 100M 44K 100M 1% /UNIONFS/var/log tmpfs 2.0G 8.0K 2.0G 1% /tmp udev 20M 0 20M 0% /dev tmpfs 2.0G 0 2.0G 0% /dev/shm When I connect USB stick it gets recognized and I can see it in the PCManFM, so I suppose the infected hard disk is infected with some very sneaky virus or something like that. I guess only thing to do now is to learn how to play with 'testdisk' tool, and that will take a while. Thank you Mr. Schulz for your time and effort.