There's a similar thread here...
http://shoutbox.menthix.net/showthread.php?tid=29...d=289365#pid289365
For other files, why not search the web for the filenames to get more information about them? It's hard to say what's safe to delete, because every computer is set up differently and has different programs installed.
I know you can safely delete File000*.chk... those are pieces of data scandisk recovered, and are usually just junk.
All of the folders should stay, because they're probably either part of Windows or places where programs are installed.