You can't turn off shared memory unless you disable onboard graphics and add a video card (if thats possible on the laptop). You might be able to adjust the amount used. I have 3 PC's with onboard INTEL GFX and in the bios there's settings where I can change the amount shared. 1 has 8/16/32mb, 1 has 16/32/64mb and one has 32/64mb.

You could boot into bios and check, myself I'd leave things the way they are. 1gig should be plenty on the laptop