I beleive you are in F1 visa. So, you are an exception for substantial presence test. This mean you have to file NR (Non resident) return. But since you filed ordinary 1040 last year, you may wanna file ordinary 1040 this year and hope IRS never catches the mistake or you may wanna amend a 04 1040. I do not think IRS has anyways to find out the staus of the person filing the return. But I cannot gurantee on this one. I see lots of international students filing 1040 and not 1040 NR. There is an exception to student where they can file 1040 instead of 1040 NR if a student resided in US as a student for more than 5 calendar years. hope this helps. Happy new year peace out