I know this thread has existed for a long time, but there are many people may want to find a way safely and flexibly resize the system partition rather than use build in disk management. And I noted on this thread have not provide the flexible and easy way to extend the partition. Before you may know Partition Magic but now it has been out of date, and now there have a alternative software AOMEI Partition Assistant which could manage this flexibly and safely. It is worth to try this software.See their official site: http://www.extend-partition.com/