there are many ways but try this one.
enter security passwords randomly whichever comes to your head.make as possible correct guessess.it may open.if not after a few try it will block and ask for pin if u remember the pin enter it or guess again .after a few entreis it again block and ask for""""PUK"""" after 3 wrong entrie of puk ur phone will block.then simply call your service support(the company which provides telecom services on that phone say vodaphone and thay will unlock your phone in no seconds)