Car wont change up from first gear (C200 1997)

[pedroc]

Dear all,

My 1997 C200 Auto was fine earlier today. The engine was warm from a recent drive but when restarted it wouldn't change up from 1st gear in either drive or shifting the stick. Clunky from neutral to drive. Okay in reverse

I've heard it may be a simple computer reset but would value any input on how this is done or any other ideas given my obvious restriction.

Thanks.