Laptop display problem

I have a Toshiba Satellite M35X-S111 running XP that is 2 years old.

Lately when I've been typing, the display will fade temporarily, usually from lower left (fully black) to upper right corner (dim but viewable). The problem appears when pressing on the left side of the keyboard, but not all the time.

From reading the forum, it sounds like the inverter might be loose. Is this a plausible diagnosis? I'm wondering what else could cause the problem and how to fix it?

Other things of note: the Shift keys work intermittently and are the original problem source b/c work when pressing harder, hence something below the keyboard is loose or now broken (my fault, too late now). I'm a student who uses a laptop in class, so using an external keyboard is not a viable solution.

Thanks for any help.