MacBook Pro (mid 2009), strange display problem

Question

Hello everybody,
This is my first post here, so thanks everybody who will read my post.
In February 2010 I bought two MacBook Pro 13 inch, for me and my girlfriend. Both of them are still working awesome, just one of them seems to develop a problem. I will try to detail it here, just that it's pretty strange even to explain.
When I look close to the screen, in seems that the colors in the images (web page elements, photos and so on) are not smooth (when changing from one color to other) rather they have very sharp edges. Next, when I look at the open menus (ex. the Apple menu in the left corner) it has some horizontal tiny lines. More, when I move the mouse over some elements (like the icons in the bar) some small square appears (like a net). I did reload the Mac and I was able to stop the same small squares over the Mac logo while booting. They are bearly visible, but for sure are there as I compare with the other Mac which has no such problems. This small squares net can be seem all over desktop and it seems that it flickers at around 2 seconds (there, not there, there...)
I know that it may be hard for you to understand, so later I will try to add a screen capture, if you don't understand my issue.
I do not have this issue if I connect an external monitor! So, I don't believe is from the graphic card / chipset.
If anybody encounter this kind of problems please give me an advice. Please consider the following:
- I'm pretty good with technical stuff, so don't be shy to give technical details
- I don't have Apple Care
- I have been already to two authorized centres (I live in quite a small town in Austria); one told me that they will open in 3-4 months, the other told me that they can send it to Vienna, but it will take about a month and will be very expensive around 700-750 euro (aprox. 800-850$). How they know it will be expensive if they don't know the issue?!. I assume that they mean full replacement of the display, but in this case I would rather sell it for spare parts and buy a newer one
- There is another authorized repairing centre at about 60 km from my city, I will try to make them a visit tomorrow, still I would glad if somebody can give me a hint.
- As I extended the memory in my Mac (2GB to 4GB) I know the layout inside the unibody case, just if you want to tell me to check some cables (btw, this with the memory upgraded is the one working, the other one was never opened or technically touched in any way).
Thank you all  and have a nice day!

Answer 1

OK, if anybody is curious, here is the outcome. I took the device to an Apple authorized repairing center and they told me that the display it's the problem. I didn't get details (but I'll ask when I'll pickup my device) if the LCD was damaged, or some cables, but they said the whole display need to be replaced.
The prices (in Euro, but you can make the conversion)
- the initial checkup and problem identification: 80 Euro (I have to pay this only if I choose not to repair the device at their service)
- the repairing (display + work): 500 Euro
Not to happy to pay such an amount of money but what can I do?
Nevertheless I want to believe that this was somehow bad luck, as I have more than four Apple devices that run just fine.
Best regards,
Calin