Something that we all need to be aware of as computer users is the
properties of files. I wonder if windows has a bug and is archiving files or something like that and files that could be used once are now unuseable? It sounds like only newborn files are useable. I will test this possibility over the weekend. I'm sure someone else can get on it before that.
(if this is happening then the quick remedy would be to once again change the property to a useable status. Long term-fix or reinstall Windows)
