There's a thread on UBI's Community Help forum: how to get il21946 to work with win7 FIX
That might possibly help you installing a clean version...
As for the current config: Try and run it with sound disabled. If it runs better, then try 'No hardware acceleration' or 'safe DirextX settings'.
From what I read about this laptop on the Internet, to get it running good/better, me thinks you need to focus on grapics settings... turn 'm down, forget about stencil buffer and perfect mode and stuff, keep it simmle,,,