Legal Question in Business Law in Massachusetts

This is not the forum to answer the question as it requires a great deal more information. Certain data is protected by statute both state and federal, other there have been law suits to protect certain material. If the material is governed by a confidentiality agreement, even if you are a "innocent bystander" you could be sued and if the data is licensed under a software license or similar matter you could be sued as well.

Without more information no one can give you advice as to your ability to use or sell any information left on the computer.

However, without knowing what kind of data it is, I am inclined to advise you not to sell it, distribute it or use it in any manner.