Dell 962 on/off malfunction

In process of installing new driver and firmware for 962 with XP operating system, printer on/off button became inoperable and all three green indicator lights ( for copy-scan-fax modes) blink simultaneously. i have tried to reboot by unplugging both the brick and the power cord, to no avail. When i reinstall the driver it does not recognize that the printer is connected since i cannot turn it "on". All i get are the blinking mode lights.

Any solution?

Thanks