Please help! CC files accidentally converted to Paint, iTunes, etc files!

@rosemow (The file is a notepad file) So on the second link, correct me if I'm wrong but, I learned that you had to extract the file with 7zip. Though when I try to I get shown a screen saying:

Elapsed time: 00:00:00 Total size: (It says the size)
Remaining Time: 00:00:00 Speed: (It says the speed)
Files: 0 Processed: (It says a number)
Compression Ratio: Compressed Size:
Errors: 1


(file name)
Can not open file as archive (Then it only gives me the option to close)

What do I do in this situation? I'm so confused!