My laptop (HP Pavilion) is more than 1 year old but was working fine. Then about couple of months back, there appeared ONE vertical line on my screen and I was told that I might have to change the screen!! So I ignored it and continued to work on my laptop. In the past week though there have been more lines appearing and its about 27 on last count.
I have seen this issue before with Desktops, in most cases its the graphics card getting old and the solder starts to separate, test it on a external screen to identify if this issue is gpu related or screen related. If the screen still have the lines on the external screen its the Graphics card (GPU)