Laptop won’t load on docking station

I have a Compaq 6715b laptop (about 4 weeks old) and a HP docking station Series HSTNN-IX01. Up until today I could push the laptop onto the docking station, push the station’s power button and the laptop would load and shut down normally. Today the laptop won’t load Windows XP or shut down if its on the docking station. Programs hang and when I remove the laptop from the docking station things carry on running as they should. Can anyone please tell me how to fix this unusual problem before I drop both units out the window.

Thanks
bruce