To change which wordlist you are using click on the Wordlists menu item and select Replace Word Lists.

(In version 1 there is not a replace option and so you first remove the one that is currently in memory and then open another.)

This will open the Wordlists folder in your WWS2000Work directory. Click on the list you want, for example the AllCo99.wus then click Open. (All wordlists have the file extension .wus).