The holy grail of volume extension must surely be the system partition. The big C.I normally use GParted to extend partitions (including the system partition), which is a truly marvelous tool, but requires a reboot onto a bootable CD (or USB key) for the most part. I had need just now to extend a system partition on a machine I don't have physical access to, and so can't put in a bootable disk. The Windows Diskpart tool won't extend system partitions. BUT... I just came across a little tool for extending volumes offered by Dell, and it can extend the system partition just fine. Doing this poses some risk I'm sure, so always always make sure you've got backups. Also, if your page file is on the partition you want to extend, I'd move it elsewhere first. Otherwise, you're good to go.