How to Extend a Disk Partition in Windows

Reader Sheila writes: Could you tell me how to "departition" a hard drive? That is, I would like to combine two partitions. It is not clear how to do this without disaster!

I'm assuming you want to combine two partitions, at least one of which has data on it, and you don't want to lose your data or have to reinstall Windows. (Many computers used to ship with partitioned drives due to limitations in older versions of Windows, and I'm not just talking about those small "recovery partition" used for reinstalling the OS. You should not mess with recovery partitions, which will typically be under 8 to 10GB in size.)

Let's first consider extending partitions. Good news if you're a Vista user (hey, you knew it was good for something!): This is built into the OS! If you have unpartitioned space on your hard drive, you can simply go to Administrative Tools in the Control Panel, then click Computer Management > Storage > Disk Management. Find the partition you want to extend (usually the C drive), then right-click it and click Extend Volume. (See screenshot for details of what this looks like.) A wizard will walk you through the rest of the process. You'll have to have blank space to extend to, which means deleting the partition you want to extend into: If this has data on it, try copying that data to a USB hard drive (hopefully you're using one for backups already!). Be creative. It's only temporary until the drive is much larger thanks to your partition expansion.

Of course, I assume you're actually on Windows XP. There is a utility called DiskPart (which runs at the command line), but it's difficult to use, and I don't recommend you try it if you're a novice. (If you're determined—it's free after all—you can find instructions here. Again, remember you'll need to clear out some blank space by deleting that second partition first with the Administrator Tools.)   

A better bet is to use third-party tools, either Norton PartitionMagic ($70) or Acronis Disk Director ($50). Both work well, and both have the advantage of letting you combine two partitions without losing data on either one. So you don't have to delete one partition and create blank space before running the program, which is really convenient. Using either tool is quite simple and self-explanatory.

Finally, if you're wiping a drive and repartitioning from scratch—that is, you don't mind losing all the data and starting from scratch—you can use either FDISK or the Administrator Tools control panel to delete all the partitions from a drive, then recreate the drive with a single partition. Here's instructions for FDISK can be found here, or check out my piece on partitioning with Admin Tools here.