Light switch won't turn off after fitting a new light bulb
Since you mentioned the switch would make an audible &quot;click&quot; sound before the replacement and afterwards it doesn't, you should investigate the switch further.
This is easy when you use some sort of instrument that tests continuity. Use a Digital meter set to Ohm's or assemble one by wiring a battery in series with a flashlight bulb.
By connecting a lead to the switch terminals both instruments will show if there is a continuous flow of electricity through the switch. If they don't the switch is bad.