File compression is a very useful concept that is now becoming quite common for all sorts of media. It allows one to store tons on information in a relativly compact package. However, since the field is growing so rapidly, it can be difficult to tell what is compressed and what isnt', which is where issues originate with opening files. One rare file type is the .cbz, which is essentially a compressed comic book.
Once you have downloaded the .cbz file, right click on it. Select "Open With.." Now, go through the list of programs until you find your decompression utility or program. Select it, and hit "OK." The decompression program will now open the file.
In your decompression utility, click on the "Extract" button to decompress the files. A box will pop up. In the box, you will want to enter the directory of where you would like the files to be extracted to. It really doesn't matter where, provided that you won't lose them once extracted. Hit "OK." The utility will now extract the files to the chosen directory.
Open Windows Explorer. Browse to find the folder to which you extracted the files. All of them should now be able to be opened with a that is already installed on your computer.