If you search the forums here you should find a thread for updating your U3 to Windows 7. The update should be run on a Windows XP machine. But I don’t think it supports 64bit Win 7.
Be sure you backup your data before doing the upgrade.
Another possibility would be to;
Remove U3. It’s an option on the U3 menu.
Install the new SanDisk SecureAccess app. http://forums.sandisk.com/t5/Cruzer-flash-drives-Solid-State/SanDisk-SecureAccess-Password-and-encryption-software/td-p/217852
Install PortableApp.com’s suite of apps. http://portableapps.com/suite
