For the most part, the Disk Defragmenter application (located at %SystemRoot%\system32\dfrg.msc) that comes with Windows XP does a decent enough job of defragmenting a hard drive for most users.
But if you’re a developer, you are not like most users, often dealing with very large files and installing and uninstalling applications like there’s no tomorrow. For you, there are a couple of other free utilities you should have in your utility belt.
Recently I noticed my hard drive grinding a lot. After defragmenting my drive, I clicked on the View Report button this time (I normally never do this out of hurriedness).