You can avoid having to reactivate Windows after a reinstall by copying wpa.dbl from the system32 folder in your main windows folder, and then copying it back after reinstalling. I think this also covers Office and any other MS activated software. NOTE: this doesn't let you use it on another machine, it still checks against your hardware configuration on startup as before. Once activated PS stores part of its key on track zero of your hard drive, the reactivation in this case just puts the other files in place but doesn't use up one of your allowed activations. The lack of backward compatibilty in AI is a result of the new text engine, and was announced before the product shipped - you should still be able to use File>Export to save back to earlier versions. As far as I am aware PSD files (and layered TIFF files) remain backward compatible - make sure you aren't using the new format needed to support larger file sizes, which isn't compatible. InDesign was meant to save back to ID2 but apparently they found it impossible to implement at a sufficiently high standard - this could have been more clearly stated, especially as it is still listed as possible in the printed and online docs (but not the readme).