Hi, Jeff,
Probably, you've burnt it. You didn't specify your chip, but if it worked initially (that is rather odd), that means that the input was in LOW state. Naturally, having applied the VCC you burnt it very quickly (the outputs of the 51 contollers are not symmetric, you can apply ground to an output in 1 state, but you cannot apply VCC to an output in 0). You should better take as a rule never to apply VCC directly to anything. As for your application, try to change the polarity: you configure the pin you will use as input to 1 and you apply ground as active signal.
Regards,
Michael.