Not sure about a Vista for Dummies book (if it's not there, it probably will be soon) but one book I like is "Windows Vista Secrets" by Brian Livingston ^ My neighbor has a copy, and from what I've found from borrowing it, the book does a nice job of explaining lots of the workings of Vista without going into lots of technical type details (so if you're looking for things about the really inner working of Vista, I'd not recommend it for that).

I also second the recommendation of getting AVG for your anti-virus needs.

And as far as a printer goes, most companies have put out updates to older drivers allowing older printers and other devices, like video and display drivers, to work with Vista (Last month I got a new Dell desktop w/ Vista installed, and the 2 month old display driver installed was incompatible, so I had to download an updated version for that). I've got an early Canon Pixma printer (got it early 2006 - pre-Vista), that, after installing the older driver, and the update from Canon's website, the printer works just fine. It's possible that P/USB adapter may have an updated driver for its product.

Frank