I got some lines almost 1/3 at the bottom of my screen, how can I delete these lines,
They are clorored lines

Sounds like your screen or graphics card are on their way out.
Have you tried hooking it up to a monitor to check which piece of hardware it is ?

Suddenley, I have colored lines verticaly almost 1/3 at the bottom of my Dell laptop.
How can I remove these lines?

As said above, try hooking a monitor up to external display on the laptop and see if the lines appear there... that will help diagnose the problem.

I would also suggest a driver update.