I recommend you to install a testlink stack in the S Drive and migrate the DB data from your old drive to it.
Bear in mind that all routes in your installation are set to be in C:. You could manually set a symbolic link between C: and S:, so everything would be present in C: too and redirected to S:. This, however, may present performance consequences undesired, and is therefore not recommended.
If there is anything you didn’t fully understand, please, don’t hesitate to ask us again. We’ll be more than glad to help you.