When can I apply for citizenship? After 3 or 5 years????

Since you are no longer married to your U.S. citizen spouse, you can file 4 years and 9 months after becoming a U.S. permanent resident.

I am an F1 student in the US. Can I sell back my piano that I bought here?

As long as you are not in the business of selling things, you can sell your piano. You will need to consult with a CPA regarding the tax issues.

After what stage (i.e. after PERM approval or after I-140 approval) can I retain my priority date for future use?

The I-140 needs to be approved in order to retain your priority date. Please note, however, that the I-539 application asks if an immigrant...

I just had my PERM approved and haven't yet filed for I-140. Will I be able to change my status from H1B to F1 to pursue my MBA?

Yes, the approved PERM should not prevent you from changing your status to F-1, assuming you meet all the requirements (including demonstrated...

I'm student F1 visa and my wife is F2 and she gives birth a week ago in Pocatello, ID. Can I apply for SSN for me ?

No, the fact that your son is a U.S. citizen does not give you any right to a SSN. As an F-1, which you presumably continue to be, you are not...

Traveling dates on I-131 Advance Parole form and reason for traveling (marriage-based green card application, AOS from o-1 visa)

You don't need to worry about the dates of travel not matching up. You can also simply put "visit family" or you can state your father's health...

Criminal history for marriage-based green card, AOS from O-1 visa

If you are doing adjustment of status, you will be fingerprinted and the government will do it's own background check on you - no need for police...

After we marry, may my Chinese-international-student girlfriend receive an extension on her US stay while her i-130 processes?

Assuming you are a U.S. citizen and filing everything together (I-130, I-485, etc) - which you should, if you are a U.S. citizen, your then-wife...

You should still appear for the biometrics appointment, otherwise your application will be considered abandoned and denied. Your I-765 may be...

Are you a legal resident if your I-751 is denied but you receive I-551 in your valid passport?

You should meet with an immigration attorney to discuss your situation. If your I751 was denied how did you get an I-551 stamp ? Presumably you...