I've had this happen a couple of times, at first I thought I did something.
Example, the other day I was looking for an address of an old friend, I couldn't find it, but knew I had it on an envelope file from Print Shop. It was on my F drive so I went looking for it and found it. When I double clicked on it, windows 7 showed it as gobledy gook for the address. I tried to use Microsoft word, but that didn't work either. Then it hit me, this is Print Shop! So I opened Print Shop, and now the envelope file is gone, completely missing from my computer. I still had the window which showed the file open, and it was gone from there and I can't find it anywhere.
Anybody else having this problem? Any ideas what's going on?