I have to change a file extension to .zip from the .abc it came in in order to unzip it and extract the file then take the file and put it on a floppy disk. I have been trying for 2 hours now I NEED HELP!PLEASE

Where are you stuck as what you've described seems quite straightforward.

To rename a file, RIGHT click and select rename, then simply delete .abc and change to .zip
Unzip is normally a case of double clicking the zip file.