Is this a bad sign?

[Ravia Devaia]

Hello everybody.

I am using an old computerscreen that is about to get 6 years old in may. And I've had this problem for a while now.

So, the problem is that windows burns into my screen.

I was watching a video for about 2 minutes and noticed the advertising was burned into the screen. Just 2 minutes!

If you see that advertising in the right of the corner.

As you can see in this picture it's burned into the screen and I was able to read the text clear like the screen showed the image.
And after around 10 minutes it's gone.

This is a 6 year old Dell 1905FP screen that I use daily almost the whole day.

Thanks for reading the post and maybe telling me what is wrong.