I thought this might be useful for someone else, here's how to add NFO filetype to the Windows 7 preview panel :
Note : This tweak involves registry modification as well as changing a file extension.
- Open a notepad,
- Type (or copy-paste) these registry entries :
Code:
Windows Registry Editor Version 5.00
[HKEY_CLASSES_ROOT\.nfo]
"Content Type"="text/plain"
"PerceivedType"="text"
- Save as "previewNfo.reg",
- Double-click on this newly created registry key :

- Press OK :
Et voila :
Ok, it doesn't look good with heavier ASCII art. But it's a preview. If you know how to tweak it even better, feel free to add/comment !
You can do the same with .SRT file (subtitles). You can do it with basically everything you open with notepad :
Code:
Windows Registry Editor Version 5.00
[HKEY_CLASSES_ROOT\.srt]
"Content Type"="text/plain"
"PerceivedType"="text"
.CFG files :
Code:
Windows Registry Editor Version 5.00
[HKEY_CLASSES_ROOT\.cfg]
"Content Type"="text/plain"
"PerceivedType"="text"
Have fun !