Hi kok wee ng,
It sounds like either your graphics processor in your TV is going bad, or the LCD is starting to break inside and not display images correctly. I would try messing around with some video settings on your TV to see if the various lines get stronger or lighter with adjusting the color, contrast, etc. If you adjust your brightness to full and the lines are as bright as the rest of the TV, then the graphics board is going out. If you adjust it to minimum and the lines are still there, the LCD is most likely going out.
Best Regards,
Drew.