It depends what you mean by a “hard reset”. My understanding of the term is that it means turning the power off and then back on again. In which case you just need to take the batteries out and then put them back in again. However, I suspect what you really want to do is restore the factory settings. I’ve not seen this facility on a 96. The only suggestion I can make is to reload the upgrade again since something seems to have gone wrong with its installation.
I guess it’s stating the obvious but always worth starting with the simple things first, have you checked that the batteries are fully charged and in the right way around?