I need an updated map for united states and canada

SOURCE: Tom Tom 910 map update with 920 maps?

Yes, this is possoble.

Make sure you:
- Have updated to last navcore v7 version
- Have updated TomTom Home to latest version

Then buy and upgrade map through TomTom Home...

Find latest version of TomTom Home here:
http://www.tomtom.com/support/support.php?ID=3&Language=1

SOURCE: How do I unlock the Canada maps?

I had same problem, purchase Sd card, because internal memory too low for all Canada and Usa. search thepiratesbay.org for unlocker program. It works like a charm. Ps i dont know the legality of using unlocker so you may want to consult Garmin.

SOURCE: My unit came with US map, I downloaded Canada Map, but...

magellan maps can only be used once and if you downloaded a torrent, chances are its been used already

SOURCE: downloaded Garmin gps maps of europe onto my

problem is fixed - helped to read the manual.

SOURCE: Tom Tom only has Guam map since update

That is really strange!
I can only suggest that you verify what MAPs are physically on your TomTom device by connecting it to a PC/LAPTOP and use Windows Explorer to look at your GPS drive folders: should see a folder for each 'country' (like GUAM).
The normal way to check which maps are registred and loaded on your device is to use TomTom Home -> Update maps function: it will show you the status or whereabout of any Maps that you have loaded or backup and which one can be purchased.
Hope it helps: let me know how you go.
ps.i f you wisely backup your device on a regular basis (via TomTom Home or direct copy to your PC/LAPTOP), you could always RESTORE FROM BACKUP and start again.