Fredo:
You have a problem. Ordinarily the disk-cloning (data-migration) operation is practicable when the TOTAL DATA CONTENTS OF THE SOURCE DISK, i.e, in your case the 1 TB GB drive, is LESS than the TOTAL DISK-SPACE CAPACITY OF THE DESTINATION DISK, i.e,, in your case the 120 GB SSD. Obviously that is not the case in your situation.
Now...if your OS was contained on a separate partition (the C:\ partition) of your 1 TB HDD and the total data contents contained in that C:\ partition was less than 120 GB, then the disk-cloning operation would be feasible. On the other hand if the OS is lumped together with all the other data on that 1 TB HDD, e.g., your programs, personal data, etc., etc., then the d-c operation is not practicable. Do you see that?
Now there are some d-c programs that purport to clone only the OS from the source disk to the destination disk given the situation mentioned above. We have never found any of them reliable.