A fixture in my basement has a single 48" florescent tube which recently started flickering and now fails to start - it just flickers. I replaced it and have the same behavior. The fixture is at least 15 years old and might be much older.
I don't see anything that looks like a starter. I've searched around and see that the ballast may be the problem, but I don't see what looks like a ballast. It may very well be under a metal cover that runs most of the way under the bulb. Well, above the bulb actually.
According to this site, the problem might be trying to use a rapid-start lamp in a pre-heat fixture:
Because the fixture is in an infrequently used small storage room (formerly a sewing room) I bought the cheapest tube they had - but I don't see anything on it about rapid-start.
I guess I can try a more expensive bulb, and if that doesn't work, unscrew the metal cover and see if I can find a ballast. It could also be the wallswitch, but that seems the least likely culpret to me.
Any advice appreciated.