You could add an external data storage device as mentioned which would mean you don't need to make any changes at all. If you swap out the drive for a larger drive then you will need to reinstall all your software which would mean you would need all the licence keys for them to run. You shouldn't have to reregister or get another key as you are allowed to run the software on more than one machine to start with.
You could try cloning your original drive onto the new drive but some software is clever enough to know this has been done & will require re activation. Not sure if that is true of aspire.