Anonymousy, I can understand why it would be frustrating having a device startup normal one time, but then have issues with subsequent attempts. Do you receive an error message when trying to connect the second time? Try evdotech's suggestion of removing the SIM card and rebooting the computer. Also, I checked and the newest software version of VZAccess Manager for this device is 7.7.1, so you may also want to update the software.
Please try these steps and let us know of your results.
Follow us on Twitter @VZWSupport