Digital BW, The Print

We all get there sooner or later. It's sad when you suddenly can't 
save a change OR the file!	
	As an ongoing solution, routinely transfer new files to a CD-RW. 
When the CD-RW gets full, make 2 CD-R copies of it on high quality 
media and store one of them somewhere away from the other one (so if 
fire or some other failure gets one, the other is apt to be safe). 
Clear the CD-RW and your hard drive and start again. 
	A CD-RW is not good for long term data archiving, but can be used 
multiple times for temporary storage. High quality CD-R (properly 
handled and stored) is much more reliable than any of the magnetic 
media, including hard drives. Best guesses run around the 75 - 100
year range. Long before that they'll be obsolete, and you'll have to 
copy them to the latest best thing.
	Or back up to DVD-R and make a second copy when it gets full. Even 
more robust media than CD, but can't be reused.
Good luck!

Jim