Files that end in .NFO are plain text files that often contain very useful information about the files you have just downloaded. Always read the NFO file if you are having a problem! Unfortunately, the .NFO extention also has another meaning to Windows, so sometimes when you try to open these files you will get an error from MS System Information about a corrupt file. If this is the case you will also probably see the file listed with a type of "MSInfo File" or something similar. You should open the NFO file in Notepad, or any plain-text editor. More info here.