Cannot help you much as many people have given good advice.
A suggestion I heard of was to copy to a good quality cdr or Ram disc but do so every 2/3 years as the quality of storage, even HD is variable. You could also try saving in TIFF, another form of saving photographs as some files are more prone to corruption that others.
This re-copying is essential if you have treasured photographs, or indeed documents. In fact I would have hard copies made of some of them.
I hope other members can help regarding saving your originals.