Solved! Go to Correct Answer
Wanna bet this gets a "solved" as you obviously are no longer having problem of connection dropping since you can't establish it in the first place.....
The problem is with your Mac. Many users have reported problems where the Mac upgrade left thier MiFi bricked. Follow JeffR's steps to resolve the problem on your own. Try to use a WinXP computer if at all possible.
If you have a Mac "bricked" Mifi:
1. Run the installer, the Mifi will show up as a USB Human Interface Device and the upgrade will not start (cannot find the device)
2. The installer leaves a directory (C:\MiFi4510L) and there's a program called DUU_Verizon_MiFi4510L.exe
3. Run that program, it will find the Mifi, and ask if you want to enable the modem functions of the Mifi.
4. Answer yes, then disconnect and hit the reset button under the battery door.
5. Now reattach to your PC, and rerun the upgrade program. This time it will work.