Most likely, the inverter cable has some wear and will need be replaced. Might as well replace the inverter and the inverter cable at the same time. You can find instructions at ifixit.com and you should be able to find a replacement on ebay.
The important thing to pay attention to is whether there's still an image on the screen. If the backlight goes out, but the image is still there, it's the inverter cable. If you mean something else by "blank," you should let us know.
Can someone help where can i order genuine apple made inverter and cable. I am having same problem with my macbook. If someone can help me with price of the same parts too, would be great.
Alternatively, i am looking at option to dispose this macbook and buy a new one, if offered good price. I have bought this in June 2008 and model is early 2008 with EMC NO: 2242.
Do suggest an option to fix it. Prospective buyers can email me on Gurmeet.Budhraja@gmail.com - i am located in Pune, Maharashtra, INDIA.