Here is how to password protect zip file on Windows 7 with 7zip software.
The built in Windows compression tool cannot password protect a compressed file; therefore a third-party application has to be used. In this article we use 7-Zip utility which is licensed under the GNU LGPL/GNU LGPL + unRAR and hence is free to download and use.
Download the 7-Zip installer from www.7-zip.org and install it on your computer.
Create a folder on your computer and move the files you want to encrypt into the folder.
Right click on the folder and select “7-Zip” and then select “Add to archive”.
In the “Add to archive” panel, choose “zip” as the archive format.
Go to the encryption box on the right hand side of the panel, and enter your password in the “Enter password” box and input it again in the “Re-enter password” box.
After you have done this much, click “OK” to finish the procedure.