The reason why all of the new TomToms since September 2010 (such as the GO1000 range and all VIA models) do not show up as a drive on the computer is because they are using the Linux based file systems instead of FAT/FAT32.
This wasn't a choice by TomTom to make it harder for us to copy or crack their devices. This was done because Microsoft successfully sued TomTom for using the Microsoft FAT and FAT32 file systems on a Linux platform, which Microsoft claimed it was an infringement.
Therefore TomTom were forced to use another file system other than a Windows based one. TomToms run on Linux anyway, so the choice to use Linux file systems do make the devices run faster than ever before, as their file systems are generally more reliable and capable than the older FAT/FAT32. This is a positive for customers, but it's a negative for us who want to update our new TomToms by sharing files with each other, as we do on here and other forums.
The only way to currently update the new TomToms is to use their program called "MyTomTom," although you have to pay for updating most things like new maps and safety cameras.
So far, nobody has been successful in trying to "crack" this new system, or rather make it possible for us to update the new TomToms using Windows Explorer. One must wonder though... how hard can it really be??