I have a fresh clean install of Vista with SP1 on my HP laptop and it's the only program on it. I have download the free version of ZA and when attempt to install it, I get this message: This version of windows is incompatible with this software. I have tried installing in safe mode and it doesn't work either. Running the installer as administrator doesn't work either. I've done all the updates and it still won't install.

What's wrong?