Download Notepad++ and go to S:\Digitization Team\n-Gram\ and copy the combine.dll file into the Notepad++ plugin folder. Other software can be used to do the merging, but make note of the encoding (UTF-8) and the filename scheme (Watson record number).
Here’s how to merge the text w/o Notepad++:
http://www.wikihow.com/Merge-Text-(.Txt)-Files-in-Command-Prompt
And to copy the prompt from the above [copy: for %f in (*.txt) do type "%f" >> output.txt] into Command Prompt, you can copy as usual (command+c) and paste into Command Prompt with the following “alt+space+e+p”