If you really do want them in a text file, then the old DOS command-line may be of service:
- Open a command console (CMD.exe in windows 7). Press WinKey+R, type cmd & Enter.
- Browse to the folder using dos command CD (for change directory). This is the hard part :ugly:
- Type the DIR command with /B switch to show "bare-bones-list" and wildcard only DWG files. Then redirect the output into a text file. E.g.:
DIR /B *.DWG > MyList.txt
If you want each to have the path as well and also have all subfolders under the current, then include the /S switch thus:
DIR /B /S *.DWG > MyList.txt
Edit: Nearly forgot, there' is a new thing in Vista & Win7. While browsing to a folder (any explorer window, including acad's open dialog) hold down the Shift button & Right-Click on the folder - you should now have a "Open command window here" option in the popup menu. That way you can omit steps 1 & 2 above.