Al, GENTLY use a flat-head screwdriver to break the seal (be careful not to damage the gasket!) Some PBs say that you have to replace the gasket when you change the bulb - but I disagree! Perhaps a little silicone or Teflon based lube is in order but, unless the gasket is wrecked, just reuse it

If you need more help on this - I'm here almost every day