What are you getting (Wrong password? Missing volume?)
Multi-part archives (part01, part02, etc.) are usually hosted on file-sharing sites. If you have the link to "Part 07," try manually editing the URL in your browser address bar: Change part07 to part08 Download S68AT02 LF1V052 part08 rar
Use the latest version of 7-Zip or WinRAR . Older versions sometimes throw a "Checksum Error" even if the file is fine. What are you getting (Wrong password