Can't Remove the Six Side Screws Holding the Screen Down.

Hello all,

I have recently started to take apart my iPhone 4s to fix the screen and the stuck power button. The whole process was simple until I got to the last 6 screws on the side which are holding down the screen. What ever I do they all refuse to turn. I had no problems with any other screw on the phone. Any advice on loosing them would be greatly appreciated.

Thanks in advance,

-Zach