Don't put any money into an older TV, you could have bought a new one for less already.
If it's not the lamp it could be something else. Have you tried different inputs?
I suggest you look for a new TV.
Here is a decent 42" one, just make sure it has the inputs you need, looks to be mostly for HDMI devices http://www.walmart.com/ip/Sanyo-42-Class-LED-1080p-60Hz-HDTV-2.9-ultra-slim-DP42142/21118777
You can also find many used ones on craigslist, it's where I got my 37" 1080p Vizio for under $200.