This is exactly the approach that Microsoft seems to be taking.

As part of its growing effort to thwart piracy, Microsoft is offering free photo slideshow software to customers who verify that they have a genuine copy of Windows.

Microsoft on Wednesday released Photo Story 3, the latest version of its software for creating photo slideshows set to music or narration. The previous incarnation was sold as part of a $20 digital media bundle known as Microsoft Plus Digital Media Edition.

This time around, Microsoft is making the software available free of charge, but it is requiring customers to take part in the Windows Genuine Advantage pilot program. In the program, people use an online tool to check whether their PCs are using a properly licensed copy of the operating system.

Originally envisioned as part of Windows XP Media Center Edition 2005, and the successor to the most exciting application in Plus! Digital Media Edition, Microsoft Photo Story 3 was instead realigned as a standalone application that all Windows XP users will be able to download for free. And bravo to that decision, because Photo Story 3 is, arguably, the greatest tool ever made for digital photography enthusiasts. In this review, I'll examine the new features in Photo Story 3 and discuss how much it's improved since the Plus! Photo Story and Plus! Photo Story 2 days. But let me cut the chase right now: If you use Windows XP, you need to download Photo Story 3 immediately. It's that good.

Download your copy of Microsoft Photo Story 3 here.
Read full review of Microsoft Photo Story 3 here.
Read CNet: Microsoft battles piracy with free software