I purchased my G74SX a few weeks ago. The only complains I have so far is the spacebar issue (it not registering keystrokes on the far left/right side) and the mouse. I'm not sure if I should send it back or if it's just low quality?
When I picked it up I was suprised because I had no clue it was included, and it looked really slick. But when I click, it moves. Even if the mouse stays still, it still moves the cursor when I click which makes it kind of useless so I swapped it for a cheap $10 mouse and I can now use my laptop again.
If you did disable your touchpad, it might be the bad one in the bunch. The occasional mouse has a mount inside break off, and it causes the innards to move, which would make the optical eye register movement.