Windows Activation Problem
My laptop died recently. I removed the hard drive and converted it into a virtual machine using VMware Converter. I verified the virtual drives by mounting them as disks using VMware’s Disk Mount Utility. Then I ran the VM in Player and hit the Windows Activation screen. This is expected because the hardware has changed radically from a Sony laptop to a virtual machine. Unfortunately, my previous XP license key did not work. I called Microsoft’s Activation support as directed by the wizard. The computer said I had an invalid key, so I talked to a customer service rep who also told me I had an invalid key. The rep, of course, is a moron who couldn’t explain why this might be the case. It turns out an OEM license (pre-installed OS) is only licensed for that machine and cannot be transferred to another machine. However, activation still failed even if I type in a legitimate retail key for XP. Now I was stuck.
I need to change the key, but the activation wizard won’t let me use the computer to fix it. One of the screens on the wizard has a link to the Windows Activation web site. Click that to get a web browser. Go to Google and search for Windows Product Key Update Tool. Download and run it. Enter your legitimate retail Windows XP key and restart the computer. Everything should work now. I had to uninstall all the laptop drivers and install VMware tools to get good performance. It’s working great now. The moral of the story is that Windows Activation sucks, the license for the OEM version of XP is unfair (can’t transfer to new computer), and customer reps are useless meat puppets.
Handwaving 
I agree that the OEM license sucks, because the inability to transfer to a new PC, but the same license is cheaper than a retail license. You have PAID for that OEM license and you have also no right of help from Microsoft, except if you PAY for help.
Unfortunately, the product key update tool doesn’t work for Tablet PC edition. I have a tablet PC that didn’t come with install media but does have an OEM license. I seem to have absolutely no way to actually repair the installation, since nobody has an ISO of the OEM install media – all I can find is the MSDN version, with a long-since-revoked key.
As always, piracy is the easier option.