I started my last menstrual period on 27-01-2012, had sex on Thursday 02-02-2012, took postinor2 tablets for prevention 0n Friday 03-02-2012. Can I get pregnant

To early to tell conclusively.

ANY time you have penile insertion you incur the risk of pregnancy. The only way to tell is by taking a test a couple of weeks after you miss your period.

You have reduced your risk greatly by taking the tablets, but no form of contraception, even emergency birth control, is 100% effective. Odds are you won't become pregnant, but you will have to wait and see. Your next period may be on time or it may be off a bit due to having taken the postinor.