A friend of mine filed taxes as resident instead of non resident while she was on f1 visa since she thought that she was a resident alien. She's Turkish citizen, she did this for tax years 2005,2006,2007 via Turbotax. She just realized that this was wrong...

Will she owe IRS a lot of money if she sends the amendment forms now. She claims that FICA taxes were deducted from her pay in 2005 and 2006, since she was actually non resident alien during those years, can she actually get a refund for FICA taxes?

There is BAD NEWS all the way around.

It is TOO LATE for her to claim the refund for the FICA taxes that were improperly withheld. Such refunds claims must be submitted within three years & three months of the last day of the year in question. Form 2006, the LATEST she could have Form 843 to get a refund was 15 April 2010.

However, that three-year statute of limitation does NOT apply for taxes improperly filed if additional taxes are owed, which probably is the case for her 2005 through 2007 tax returns. The U.S.-Turkey Tax Treaty has no treaty exemption for students, and non-resident alien CANNOT claim the standard deduction, nor are they allowed to claim education credits. It is likely she claimed BOTH on her tax returns, so when she amends the returns, she likely WILL owe money to the IRS for each year in question.