What you need to do is set up a UBCD4Win livecd, boot up the computer with it and run either Joshua’s Key Reader or Keyfinder. Setting up UBCD4Win could take a while, so here’s a guide on how to create your UBCD4Win livecd.
This method has a few major drawbacks over the Hiren method in that you need a bootable Windows install and an XP install CD. This is because UBCD4Win needs to be installed before you can create the bootable CD and also requires a number of files from a genuine install CD.
1. Download UBCD4Win (270+MB) and install it on your computer.
2. Run UBCD4Win.
3. You need to select the source at UBCD4Win. Insert Windows XP installation disc and select your CD drive. If you don’t have Windows XP installation disc but your manufacturer provides a i386 folder in your C drive, then select C:\i386.
4. Insert a blank CD, select Burn to CD/DVD and click Build. The whole process will take a little while.
5. Now to recover Windows product key, all you need to do is boot up the unbootable computer with UBCD4Win. Follow the instructions until you get to a part where it looks like Windows. Go to Start -> Programs -> System Information -> Info. and Diag. Tools -> You can either use Joshua’s Key Reader or Keyfinder
5.a If you run Keyfinder, go to Tools -> Load Hive… and select the Windows folder which is normally at C:\Windows and the genuine Windows Key will be display at the right pane.
5.b If you run Joshua’s Key Reader, click the Read Remote Key button. Same thing as above, select the offline Windows folder which is normally C:\Windows. The Windows Product Key will then be shown.
These methods are confirmed to work on Windows XP, Vista and 7 because we’ve tested them successfully. See, all it took is one CD to do the job. You don’t need to have access on another working computer to decrypt the ProductID, or the hassle of taking out the hard drive and fixing on another computer. Something I would highly recommend is to burn one of these above CD’s anyway because they are great to have already to hand when something like this happens.