Badger is correct. You don't set a 'File location' in MC. You import the files from many different locations and MC will display them. So for you get your music / files onto the new hard disk and then import them into MC. All good....
OK, seems to make sense. But to be sure:
1) I copy my files from my current desktop to the new HD (after which I may delete the files from the original location)
2) I use the Tools/Import/Auto-Import function
3) Whenever I want to playback my files, MC will automatically get the files from my EHD, right? And
4) When recording/copying from now on, I will follow the same procedures as I do now, only directing the files to the "new" location, which will be my EHD, and which also will be automatically synchronized with MC.
If I got this right, thanks a lot to the both of you, if I haven't (I sometimes get things wrong), please correct me.