Garmin GPS problems

I have a Garmin GPSmap 178 Sounder. Last night, it was working fine as always until we began our run back to the ramp and noticed the countour lines were missing from the map. While I got the truck, (btw, thanks to the guy who wouldn't turn off his headlights while I tried to back the trailer down the next lane) my buddy turned the Garmin on and off and then took out the Hot Spots card and put it back in. Now it says the card is unaccessible and we can't access any lake maps. Any suggestions? It's worked fine for the last 5 or 6 years.