Around a week ago, I did a fresh install of Windows 7 on my new laptop, in order to get rid of all the bloatware. I recently received a message saying that my activation key for Windows 7 was invalid and that I needed to input a new key and reactivate.

I did some research and found out that a new installation of Windows 7 needs to be activated, so that specific installation is tied to the computer it has been installed on. This means that most likely if a major change is made to your computer, such as a new hard drive or CPU, Windows 7 may require a reactivation. Lame.

In any case, what happened to me was that I used an activation key that was for an OEM version of Windows 7. Basically, for OEM, which stands for Original Equipment Manufacturer, the activation key is tied to that version of Windows. The Windows 7 ISO I used for my clean install came from a retail version. So, activation didn't work, using the online method, which Windows 7 uses if you have an Internet connection.

Not wanting to shell out a couple of hundred bucks for an activation key when I have a perfectly good one on my computer, I crossed my fingers and tried the phone activation method. Luckily it worked! During my research, I found comments that Windows 7 can only be reactivated a limited amount of times. I hope this isn't true, since I'm the type who likes to reformat my computer every so often, just to keep things fresh and clean and a reformat would mean having to reactivate Windows.