Hi,
I am student on F1 visa in usa from fall 2007. I had been using turbo tax till now (including this year) to file my taxes. I came to know the about the 1040 NR and EZ form issues last year and I read somewhere that I would be treated as a resident as I stayed more than 300 days in US each year. But only now after reading through posts here I realize on F1 visa I am exempt to residency for 5 yrs.
In 2007, I did not get any refund, in fact I had to pay something. In 2008,2009 I had got some 800 and 1100 dollars refund. And as I am a student I used that money to pay back loan on my tution.Now I feel very sorry that I did not research this thorugh earlier and I was hoping to file my amendments.

1. Do I have to file amendments for all yrs from 2007-2010?
2.Also as I am a student I cannot immediately pay back thousands of dollars (as I did get some deductions through economic stimulus fund, eductaion credit etc). So kindly tell me what will be the kind of money that I am looking at paying back? Will I be able to waive penalty and what would be the interest charge?

Thanks in advance!
Ravi

Yes, you need to amend all your returns.
Fill out form 1040X for each year and a complete non-resident alien return (1040NR or 1040NR-EZ and form 8843).
http://www.irs.gov/pub/irs-pdf/f1040x.pdf

http://www.irs.gov/businesses/small/international/article/0, id=96477,00.html

If you cannot pay the taxes you owe in full, you can make an installment agreement with the IRS.
Have a look here for interest/penalties:
http://taxes.about.com/od/backtaxes/qt/irs_tax_penalty.htm

If you owe taxes but can't pay the full amount by the April 18 deadline you should still file your return on time and pay as much as you can to avoid penalties and interest. You should also contact the IRS to ask about alternative payment options. Here are three alternative payment options you may want to consider:

Additional Time to Pay Based on your circumstances, you may be granted a short additional time to pay your tax in full. A brief additional amount of time to pay can be requested through the Online Payment Agreement application at http:www.IRS.gov or by calling 800-829-1040. Taxpayers who request and are granted an additional 60 to 120 days to pay the tax in full generally will pay less in penalties and interest than if the debt were repaid through an installment agreement over a greater period.

2. Installment Agreement You can apply for an IRS installment agreement using the Web-based Online Payment Agreement application on IRS.gov. This Web-based application allows taxpayers who owe $25,000 or less in combined tax, penalties and interest to self-qualify, apply for, and receive immediate notification of approval. You can also request an installment agreement before your current tax liabilities are actually assessed by using OPA. The OPA option provides you with a simple and convenient way to establish an installment agreement and eliminates the need for personal interaction with IRS and reduces paper processing. You may also complete and submit a Form 9465, Installment Agreement Request, make your request in writing, or call 1-800-829-1040 to make your request. For balances over $25,000, you are required to complete a financial statement to determine the monthly payment amount for an installment plan. For more complete information see Tax Topic 202, Tax Payment Options on http.www.IRS.gov.

3. Pay by Credit Card or Debit Card You can charge your taxes on your American Express, MasterCard, Visa or Discover credit cards. Additionally, you can pay by using your debit card. However, the debit card must be a Visa Debit Card, or a NYCE, Pulse or Star Debit Card. To pay by credit card or debit card, contact one of the service providers at its telephone number or Web site listed below and follow the instructions. There is no IRS fee for credit or debit card payments, but the processing companies charge a convenience fee or flat fee. If you are paying by credit card, the service providers charge a convenience fee based on the amount you are paying. If you are paying by debit card, the service providers charge a flat fee of $3.89 to $3.95. Do not add the convenience fee or flat fee to your tax payment.