Not sure about VISTA, but up to XP anyway (and probably VISTA) Microsoft Windows would allow you to extend a volume by adding Unallocated Space from the same physical unit, but WILL NOT EXTEND A BOOT DRIVE. For that you need a 3rd party package - Partition Magic is known to do it well.
First, Format will completely erase your disk and you lose it all! (Yeah, I know, it's all there but inaccessible because the Root directory and allocation tables are blanked out, but recovering from that is real trouble!)
But even before that a Format cannot change anything about the size of a partition. All it can do is make the existing partition blank. The suggestion to look up Gparted for free use in VISTA is the best one here.
I know this thread has existed for a long time, but there are many people may want to find a way safely and flexibly extend 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. Image software is not very convenience. Before you may know Partition Magic but now it has been out of date, and now there have a alternative software AOMEI Partition Assistant which could manage this flexibly and safely.