I would imagine it would.
Maybe take out the new Graphics card and it should be Ok
I suppose if you even open it unless told to do so by whom you bought it from could also affect the warranty.
If you had problems after installing the card then I would imagine you would not be covered.
But then again that is only my views with no experiance on the matter,So best waiting for others to help.
I would imagine the FE would be one of the best to ask as he has wide knowledge of problems like that.
Maybe explain why you ask and who you got the computer from and if the company has refused to fix or repair the problem.
Like I said those are only my views and I would certainly wait for others who can explain completely what your warranty covers.