The short answer is ...Yes!
Its tempting to just leave it at that but that would be cruel
Formatting is one option but then you've got to go hunting for all the stuff that doesn't come with a navcore (like postcodes etc) so the following might be easier for you...
You'll need a navcore which tomtom will happily give you when you use the Home software so need to go hunting for that..
You'll need a map and you've already got one of those (your backup map should be fine for this purpose)
You'll need a tool to get it all ticking along nicely..I suggest Easyusetools which you've also probably already got?
Here we go then:
1) Connect to home and use manage my device to remove the "Application" installed (don't agree to make a copy as you don't know what's wrong with it)
2) Now use update my device to get a new Application (that's the navcore) installed. Dont worry if you get map error reports when it starts up just reconnect to home and update again and repeat this process until it says there are no more updates for your device at which point you should have the latest official navcore designed for your device.
3) Now you need to use your tool to do 2 things:
(for this you need to be connected to your pc and know the extension of your tomtom eg: ( F: )Tomtom XL
a) patch the navcore by hitting runmefordct and then choose option 1 followed by option 3 and just sit and watch it do its thing until it says its finished..
b) crack your map by again using runmefordct and choosing option 1 followed by option 2.
There ya go,job done! Now you know how easy it is why not grab the latest map and use that instead although make sure you check that it's compatible with your navcore. (also,don't forget that if you place the .ov2 files for the speed cameras that relate to your map inside it, before cracking as described at b) , you'll then have working tomtom camera alerts!)