Having the same issues as many others with a new 16GB Cruzer Edge bought from PC World yesterday. Not completely recognised by Win 7 64bit running on a Toshiba Satellite. Sometimes appears as a drive, sometimes not. When it does appear and you try and use it you get a Media Not Present error. Same thing in Drive Management, there’s an allocation but with Media Not Present in the detail. It works fine on other equipment. Never had this problem with any other stick.
From the number of forum entries here and elsewhere there is a major compatibility problem with Win 7 64. I suppose I will have to take it back as unfit for purpose but that entails a round trip of 50odd miles! You can take it SanDisk is off my supplier list! (and my Christmas List!!)