Change .rar file association from winRAR to 7-zip.

Certainly you need to install the downloaded 7-zip on your PC first.

There are at least two ways to un-zip the file:

1) Point mouse to the .rar file and right click, 7-zip should be in the pop up window that has list of available program. Select 7-zip to extract the file.

2) Point mouse to the .rar file and right click, select "open with" from the pop-up winodw menu. Select 7-zip from list of programs and check "Always use the selected program to open this kind of file".

The 2nd method will change .rar file association to 7-zip. You just need to double click .rar file next time to extract.

Hope it helps.