Questions about drivers reinstallation and Audio Engine prefences setting

Hello,
After consulting Cakewalk support (Joey Adams was very reactive and careful), I have to uninstall and reinstall the Roland VS700 drivers. As I'm not too used to this kind of operation, I have some questions :
In the manual instructions, it is said that ALL USB cables have to be disconnected from the computer : But this implies also that everything which is connected to usb port has to be removed : for instance my iLock key ?
 
Second question : I've to install the "D" last update of Sonar X3; but I think I've heard that, in Preference, if the Double precision audio engine (64 bits) was checked, it may cause (instability) problems ? Could you confirm ?
 
Once again a BIG thank you for your attention and help !
 
Pierre