If the only problem you have is the wrong internal filesystem then GarminCure3 should help. If it doesn't we can also try clearing NV memory.
According to the QuickCure3 screenshot your device's HWID is 851, so use this firmware: Garmin: nuvi 2x5 (GCD File) Updates & Downloads
I managed to do a hard reset on gps and now my PC can see the partition of internal garmin, but the problem is that my gps (since doesn't have any files inside now) can't stay on. keeps shutting down after 3-4 sec. And i can't put it in pre-boot mode so i can use any of the cure programs. Any ideeas ? Thanks again
Well,i have issues like that too on many sat navs,i repair garmin and tom tom sat navs on daily basis...
make this procedure:
open your sat nav and completly remove the battery
get a diferent one and put it back
and should work now
hope it helps