Cellphone interference...?

Hey there, good afternoon guys.

My notebook doesn't seem to have any problems right now, but I want to ask something in order to keep it that way. Here's the background:

My previous notebook (not a Dell) had an awful problem after something like 3 years of use or so. The screen went really really dark all of a sudden. If you pointed some light at the screen, you could still see everything there, but it was way too dark for me to use it normally. At first, it would be fine depending on the angle I would open the notebook, but it kept getting worse until it got permanently like that. I had to plug in a separate LCD screen in order to continue using that notebook, since no one figured out what was wrong with it.

Now, I have a Vostro 3550, and I noticed that the same phenomenon occurs if the back my cellphone happens to touch the area just to the right of the touchpad. The screen goes extremely dark, and reverts back to normal when I take the cellphone away. It happens whether the phone is turned on or off, but only if it's the back of the phone that touches that specific area of the computer. This is the first time, though. I found this out by accident today, it's not like I leave my cellphone there all the time or anything.

So what I want to know is: is it okay to have the notebook and the cellphone relatively close to each other (in the same desk, for example) or does it cause some long-term damage? Do you know which component is affected by this? I'm really worried now, because of my previous notebook. The cell phone is a Nokia X2-00, by the way.

Can someone please shed some light on this?