NH,
The original "unable to load operating system" message might well have been a clue!
If there is valuable data (e.g. your photos may not have "value" but they are priceless and irreplaceable for you) on the disk, I suggest you stop right now and contact a firm that specialises in recovering data from HDDs. There are some not too expensive places that should be able to help.
You are more likely to harm than good at this stage if you try to recover the disk contents, unless you really know what you are doing, and with respect, you haven't given that impression so far!
SD