File Association Issue - Now I Windows won't open certain files

Before I begin, I have no viruses or spyware as I was actually in the process of doing my weekly computer maintenance, when I opened a file and because there was no association with it, the screen came up that asked if I wanted to go online to find it or to select from a list of programs on my computer, none of them were compatible, but instead of clicking "cancel", I clicked on "o.k.", and had the "wordpad" icon.  After tinkering around, don't ask me what I did--  I ended up getting the "default" icon that (page with the "window" in the center of it) and it states in properties that the file opens with an "unknown program".  What do I need to do? 

 

Also, I have tried to do the "File Types" thing in "Folder Options" to associate the files with a program, but none of my extensions is listed!

 

Can someone please assist me?   Thanks