should have been more specific, i have the star tip screw driver, but it seems that the screws in question are made of some sort of rubber and they will not loosen or they will not simply pull out, as if they were stripped. Was wondering if there was a special tool needed.
Depending if you really want to spend money to fix blown out speakers on a mini stereo system. You could use a drill with a small bit and try to extract them that way, so lefty loosey on those. IF they still don't come out you pretty much have to get rid of the screw without destroying the threads of the object they are inserted to. Also, could be some type of glue or nut/washer holding the screws in.
Before you even do that you might want to check replacement costs for the drivers. The drivers are very cheap( if you can find them), so it might cost 1-3 dollars per driver.
I guess the next question I should of asked first is, how do you know the speakers are blown?