Logging in with a previous identity.
 

My previous laptop died.
Computer mechanic transferred 'data' over to 'new' laptop.
So far so good!
I now want to retrieve data (which might be 'hidden') from the old hard drive.
New laptop has a different user identity, and old hard drive is refusing me access.
What steps should I take to be able to sign in as my previous user?

Can you attach old HDD via a USB port and a suitable connector and then acess the drive?

Like this: Cable

I have a caddie and can read the contents of the old hard drive but I am 'refused access' to the files as I am currently logged-in as a different user.
I cannot see an option to have multiple users.

Edited to add:-
Googoo is your friend:-
How to share a single PC.
It might be difficult as I was the Administrator on the previous laptop, whereas adding a another user will not have Administrator rights.

Browse to old hard drive in Windows Explorer.
Select folder/file you wish to access.
Right click, select "Properties".
Click "Security" tab.
To right of "For special permissions or advanced settings..." click "Advanced".
Click "Owner" tab.
Under "Change owner to:" select the new user ID, and click "Apply".

If it offers the option to apply the changes to all contained folders and files, then do so.

That should do the trick.