Virtually all commercially-sold PCs come with some sort of recovery tool--an alternate way to boot your system (either a CD, a DVD, or a special key combination to press shortly after turning on your PC) that can return your hard drive to its factory condition. Thus, with just a few keystrokes, you can once again have a working copy of Windows, along with all the bundled junk you studiously removed, and none of your own files.

This is almost certainly overkill for an unbootable PC. See Diagnose and Repair an Unbootable XP or Vista PC and Six Downloadable Boot Discs That Could Save Your PC for better advise when Windows won't come up.

And speaking of mistakes, never ever run your PC's recovery tool without first backing up your data. In fact, you should never go to sleep without first backing up your data. In this day of cheap external hard drives and automated online backup services, there's just no excuse.

Okay, enough lectures. You've made your mistake. Can you get your data back?

It's hard to say. There's a slim chance you can get everything back, a good chance you'll get some of it, and a real possibility you'll get none. The problem isn't that the recovery tool erased everything on C:, but that once it finished erasing, it started laying down files. It's the overwriting, not the erasing, that destroys your precious bits.

Your chance of recovering files decreases every time something writes to that hard drive. Letting the recovery tool complete its job lowers your chances. So does booting into Windows and using the computer.

Here's another issue: The more fragmented the files on your PC, the less likely they will be successfully restored. Another good reason to defrag regularly.

How do you restore the data if you can't boot the hard drive? There are two options: Physically remove the hard drive and attach it as a secondary drive to another computer, or use recovery software that comes on a bootable CD or flash drive.

If you're comfortable with removing a hard drive, this is  the best solution. You can then install it as an internal slave drive in the other PC, or use something like the Bytecc USB 2.0 Drive Mate to effectively turn it into a USB external drive.

What software should you use? I recommend either Iolo's Search & Recover or LSoft Technologies' Active@ Undelete. You can download free demo versions of each of these US$40 programs, and use them to find out what can be restored (you'll have to buy one to actually restore anything). Whichever program you use, select the option for scanning the drive for lost or damaged partitions.

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