Changing file extensions?

Hi, I have windows ME and I have downloaded a game. Now I need to change some of the extensions on the files from Zips to Ztds. Using the rename option just changes the name of what the file is, NOT the extension. What am I missing?

 

it's been a while since i've played with "me", but i think it's the same. open my computer, go to the folder where the files are, tools, folder options, "view" tab. then uncheck "hide extensions for known file types". now, try and rename it (look at screenshots below). i'm sure there's another way, it's all i can think of right now. g/l

you might want to make a copy of the files (just in case), before you change them.