I have Easy Media Creator 9 installed on a HP Desktop computer running Windows XP. I would like to deactivate it so I can run it on a Toshiba Laptop running Windows Vista. I am not sure how to do this, and I'm not sure if this is even possible. Is this possible, how do you do it?

There is no "de-activation" process, you just uninstall it.

Go into Add/Remove programs and uninstall it.
or
If you want to make sure it is 'cleanly' uninstalled, use the Clean Install process, Just don't do the install step at the end.

*** CLEAN INSTALL LINKS ****
v 7.5, 8, 9, 10
XP: http://kb.roxio.com/content/kb/Creator/000086CR

v 9, 10
Vista: http://kb.roxio.com/content/kb/Creator/000127CR

Thanks, Larry. Certain features require activation, and I would like to use the same product key to activate it on the laptop so I don't have to buy a new product. Is there a way to do this? Thanks again.

Which 'features' would that be? Are you talking about some of the third party apps that were included in some suite versions, like Soundsoap? You should just be able to use the same keys on the laptop that you used before.

It says on the box, "Import, capture, editing, copying, burning, exporting, or viewing of mpeg-2 files, DVD-Video titles, or HD-V video and burning of DVD, mini DVD or SVCD discs requires one-time product activation via the internet. Product activation is fast, free, and anonymous." First off, I am not sure if it means one-time overall or one-time per computer. Second off, in the printed user guide included with the product, it mentions registration. Is this seperate from activation? If so, is this, too, one-time per computer? Thanks.

Yes activation is separate from registration.

You do not even need to register the software to use it. You only need to register the software once. It is tied to you not the pc.

In the version 9 video line of products, the activation is for the license to use the MPEG2 encoder. It will show up at some point for every installation (not during the installation or even upon first use usually). Even if you went thru the activation process on a pc initially, if you unninstall the software and reinstall it, you'll have to go thru that activation again.

I would not uninstall the software, from your old computer, until EMC 9 is activated on your new computer.

The Roxio method of activation is extremely poor, at best, and if it doesn't work the first time, or after 3 "clean installs" of the software, it most probably won't happen. You don't want to take the chance of losing it on the computer that works.