did I get ripped off?

[nandk]

I just bought from a pawn shop an older m-box with a protols 7 cd, when I hook it all up the unit makes an electrical hum noise, the software opens fine.. but I was wondering if this is like my amplitube program where it will hum so you cant use it unless you have it correctly registered,.. however I did validate the protools with the correct serial number, but I did notice a ilok folder in the disk? is it nesasary to use ilok? or is my unit bad? -Nick.

[TCM]

No, if PT opens then it recognized the Mbox and you can use it. The ilok is needed for Plugins that require an ilok authorization.
The hum may be a faulty wire, hardware etc.

[DigiTechSupt]

It's difficult to say if the hum means it's defective or if it's just a ground loop or some other, solvable, issue.

You should take a look at the General Troubleshooting thread, which has specific info on combatting hum or noise with an Mbox.