SOLUTION FOR READING FILES (not booting)
I had problem that VirtualBox could not boot from *.hdd file (previous *.hds in Parallels), so I did the following:
1. I have created completely new Ubuntu machine in VirtualBox with completely new HDD
2. I have added my existing *.hdd file as second HDD in machine settings
3. command sudo mount /dev/sdb1 ~/hdd2 has mounted my prev disk into Ubuntu machine
4. then I could at least copy old files from old HDD into my newly created VM's HDD
5. Removed Parallels Lite from my computer (out of dissatisfaction)
Notes:
In step 3: /dev/sdb1 is for second HDD, /dev/sdc1 would be for third HDD, etc
and also directory ~/hdd2 must exists before mounting