I'm almost certain that in the past my Dell Inspiron 580 with Windows 7 could open zip files.

Last month I had to replace my internal hard drive and reinstall Windows from the disks I bought from Dell.  Now whenever I try to open a zip file I've downloaded I get an alert which says Windows Explorer cannot open it. 

I see a lot of different programs you can buy or download for free which claim to allow you to unzip files.  Isn't Windows supposed to be able to open zip files by itself? 

Are there any free, downloable zip file openers which will work with 64-bit Windows 7?