problem with customer care

Dear Dell,

My notebook XPS M1530 doesn't work - black screen on start up.

It has exactly the same problems as on this video http://www.youtube.com/watch?v=Y3h0Tt2cWBs

And these problems are problems with nvidia gpu.
I've call to support.

Man there has told me this problem is known, warranty for such problems is extended to 5 years and they are ready to exchange motherboard. I should only bring device to service center. And I did it.

But today everything is changed. First they have found some old fluid traces under keyboard (it was tea 2 or 3 years ago) and second another man in support has told me that "doesn't boot problem" is not "video problem"...

Tell me, please, what should I do in this situation?

I need customer care. Help me, if you can.

And sorry for my english.