These sound anti tamper screws and obviousl need a special screwdriver/socket like the key spanners for some security lights that have triangular head bolts. Try an electrics shop see if they have one to fit. However you might find the cable is solder fittted inside which will mean buying a solder iron so in long term might be cheaper to buy new hair dryer.
Bob
June 2011
I can answer this question...
How do you open a Babyliss Hairdryer - triangular screws?
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Try fixfault.com to fix hairdryers.