Reading through this thread again brings back memories...
It never warped, the screws just failed. Whenever I open the laptop, the screen pushes against the bottom half of the laptop and it causes stress on the outside of the screen, which is plastic. The plastic has stressed and become curved because of this. The screws eventually became stripped and now don't fit.
Don't know if this is an error on my end or Dell's, though I tend to blame Dell just because I hate them.