Low volume tends to exacerbate any moves, and I think on Friday everyone on Wall Street is going to have skeleton crews on staff.
The semiconductor index right now is a broken index. Until it finds some support, it will continue to sell off and that tends to drag down the market as a whole.
Sometimes Greenspan tends to spin a web when he's talking, so I am not sure how many hints he'll give about the size and speed of interest rate hikes.