After I downloaded (via wifi) USA maps (6.? Gb's) onto GO 620 WiFi, it freezes after drum roll and white line has reached RHS. Nothing else happens. Have gone into system restore and connected to MD at crucial point and clicked start button 3 times and connected to pc (Win 10). MD states that restore is happening. Have tried this restore many times and same thing happens. Cannot get "into" GO 620 via MD to remove download and start again ...Have searched FAQ's and other internet sources, and cannot get any answers. Don't know what else to do. Help! Leaving for USA on Tuesday 4th June, 2019! Is there any way to factory reset and start all over again with new maps etc?