You can't deactivate an upgrade of an OS. But you can go back to factory conditions on your Vista desktop, if you know how to do that. Then Windows 7 is gone.

The interesting thing comes next. Run your Windows 7 upgrade on your laptop and see if it accepts the license code. It won't, since it isn't a re-install but an install on another machine. Then you contact the free Microsoft activation issue desk and explain what you did. Now there are two options: (1) they'll give you a new license code for free (since the old one isn't used any more), or (2) they'll have you pay for a new license code.

If you carefully read the small print that came with the upgrade, you might be able to predict the outcome of your call. If not, it's anybody's guess. Maybe it's a good idea to call Microsoft before you do it.

Kees