You can take that one step further and set it up so you can right click on the folder and write that list into that folder
Create a batch file...say in your rootdir C:\ doesn't really matter where as long as you know where it is
In the file named .bat ..you can use notepad the rename ext.
cd "%1"
dir/b/s >mylist.txt
cd\..
exit
then go to win explorer >tools>folder options>file type
click on the one called folder..not file folder..then advanced>new... then you get the new action box
1st line is what you want it to say when you right click on a folder....something like "write list of folder"

in the application used is where you enter the path of the bat file.... c:\writefile.bat
with that dir/b/s... it will write all subs.... so don't do it to far up the tree.. or run the bat by itself at the root level as it will list every file on your drive
you could take the /s off if you only need the files in the first level of the folder
caution.. you have to use regedit to delete the action which really isn't that bad.. do a search for the bat file name in regedit...make sure you type in right the first time and it will be no problem..