* Go to 'My Computer'
* Go to the drive/folder which you want to decompress.
* Right-click-->Go to 'Properties'
* If you're decompressing a whole drive then in the 'General' tab, you'll see at the bottom 'Compress drive to save disk space'
* Uncheck it and click 'OK'
* It'll take some time to decompress the whole drive contents as it applies the new attributes.
* On the other hand, if you're decompressing any file/folder then in the 'General' tab you'll see the 'Attributes' section.
* Click on 'Advanced'.
* There also uncheck the same option as mentioned above.
* There you have uncompressed file/folder/drive.
* Now they are listed in Black colour!!
That's it!!!!
And still if your PDF files don't work as I've told you earlier (and that certainly the case is), the files are themselves corrupted and you did the decompression in vain. So you'll have to get those PDF files again from where you got them....
Happy decompression session mate!!! B-)