You may need two people. One to push down on the proper size screw drive and the other person to put vise crips around the shaft of the screw driver to turn the screw driver. Careful not to strip the screw head.
Sometimes the hoses are hard to check. Try taking the end off and make sure you can run a smaller hose pipe through it. A lot of times I have pushed a wire through and that was no enough to clear the clog I needed something bigger to find or remove the clog. Still think it is clogged up with dirt. ;-)
Five or so years old Sony DSC-W1 with a battery door problem: small plastic latches that catch and hold the sliding door in place and make contact with the batteries have worn or broken to the point that I need to wrap a rubber band around the right side of the camera to keep it closed. Ugly hack, and the rubber band gets in the way of using the dial and some controls on back Maybe this will help. On ebay for 6.99 New Battery Cover Door Cap Lid Holder For SONY DSC-W1 W12 Camera Repair ASSY