Locked Files

Please bear with this as this is a little longwinded!
After managing to kill my original MacBook Pro with a cup of coffee, I transferred the files on the hard drive to my brother in laws Macbook. The dead MacBook Pro was then sent away to my insurer who insisted that the hard drive was inside. My insurer gave me a brand new MacBook Pro but after transferring my files from the brother in laws MacBook I am unable to access them. Ive tried all the obvious things with no luck. The files contain all my photos from last 10 years so any help is greatly appreciated.
Thanks!