No power in a fluorescent tube lamp
There is one part you haven't tried, and that is the "ballast".   Fluorescent lights aren't like incandescent lights, they can't be connected directly to mains power.  They need a device to limit how much electric current they draw, and that device is the ballast.  

Ballast failures on older lamps are very common.   If you want to replace  the ballast, you can get a modern electronic one that will perform much better.  However the wiring will be different, so you may need to rearrange some wires.  Follow the instructions of the ballast faithfully, don't wire it wrong simply because the ballast is already wired a particular way.   

Another option is to convert to LED lighting.  In this case the ballast is removed entirely and mains power is sent direct to the LED light (through the switch). They make LED light "tubes" that take mains voltage and fit where the tubes go.   Beware of "plug-and-play" LEDs that require a working ballast to be there.