If one of our products, such as Super-NZB, fails to process the PAR files that it downloaded, you can easily run them through QuickPar, or MacPar Deluxe if you are using Mac OS X. Both program are free.
On Windows, download QuickPar. Once you have it installed, just double-click on one of your PAR files. QuickPar will start up and process the PARs. If there are RAR files associated with the PARs, you can extract them with WinRar, which is also free.
On Mac OS X, download MacPar Deluxe. Once you install it, all you need to do is double-click on one of your PAR files and the program will start up and process your PARs. If there are associated RAR files, it will also extract the files from the archive automatically.