Garmin cure3 needs preboot visibility only, try it and follow Neil's post here:
[Only registered and activated users can see links. ]
After cure probably you will be able to remove files plugging it USB to pc.
Remove any GUPDATE.GCD from Zumo, Express wrote a file that bricked it.
Reflash then original firmware.
Please read with care kunix's cure post before doing anything Be sure to use your unit HWID firmware.