Double-check the electrical source (plug) you have it plugged into with another device.
Just because the bulb "looks good" does NOT mean it IS good, also. If the electrical source ("the plug") is "hot", then the likely culprit is the bulb. Next would be the electrical switch - "fiddle" with it a bit.
(work it like a toilet that is problematic: jiggle the handle. wiggle things a bit. yell at it. whack it a few times)
If that doesn't work, check your warranty to see if a repair is covered.
Answers & Comments
Richard:
Double-check the electrical source (plug) you have it plugged into with another device.
Just because the bulb "looks good" does NOT mean it IS good, also. If the electrical source ("the plug") is "hot", then the likely culprit is the bulb. Next would be the electrical switch - "fiddle" with it a bit.
(work it like a toilet that is problematic: jiggle the handle. wiggle things a bit. yell at it. whack it a few times)
If that doesn't work, check your warranty to see if a repair is covered.
(don't "whack it" so hard the warranty is void!)