Thanks for all the useful information that you all have posted here. I have a question. My statius changed from OPT to H1B in August 2005 and I am thinking of filing as a non-resident as per Atlanta Tax Expert's advise. My employer has also been deducting social security and medicare taxes since Feb 2005. If I file as non-resident do I have to request a refund of all the SS and medicare taxes that were withheld from my paycheck or only ask for a refund of the SS and medicare that was withheld while I was on OPT?I have used a software called CINTAX to calculate my taxes but it says that I need to PAY some amount ot the IRS even though my taxes have always been withheld by my employer. Am I missing something? Please advise. Thanks.