Well it was put there to stop other people snooping or, in the even of the laptop being stolen. so it could not be used.
Now your story may be Genuine.
But sadly due to the first reason, no one will likely help you on this matter.
Because it is circumnavigation of security protection.
Or wipe the current OS on the laptop and start again with a fresh OS of windows 7.
That is all the advice I can give you for two reasons, it will wipe any sensitive data your own uncle may not have wanted you to see. Protecting it After all it was his laptop and his right to do it for that reason. If it is stolen then you have no hope at all, no one on here due to knowing it will help you any much more than this.