By accident I stepped on my $99 HP Touchpad. The screen broke and it was as good as gone.
I started by trying to use a screwdriver to pry open the case but it started hurting the plastic. I opted for a set of spudgers and the process went much more smoothly.
Use a pair of spudgers to open the case. Pry open with one and use the other one to keep the case opened as you go for the next section.