gti clocks

picked up a h reg gti cabriolet, been in a dry garage for 4 years! sat in the car while the bright spark owner put a jump starter box on it and watched the clock go from the time to jibberish in 0.00001 of a second. its stayed that way ! any idears what to do next ? can i get it reset ?

pull the fuse - wait a few secs and replace it - should reset itself

thanks for that ! the battery was a dudd and when i replaced it the clock came back on !! result !