A while back I removed the body of my E71 in order to clear the dust from under the screen. Easy job. Now due to 15 months use, I want to replace the whole body (battery cover, keyboard, screen cover and rim). I've hit a snag though. During the dust removal process I seem to have overtightened the screws shown below and through forcefully trying to remove them with a screwdriver seem to have sheered the heads of the screws. This means all the screwdrivers I have tried cannot free the screws. Any way around this at all? Would love to have it looking like new again.
I have tried t4 and t5 screwdrivers
http://thenokiablog.com/wp-content/uploads/2009/04/unscrew-t4-screws.jpg
