Can I stay in U.S as long as my request to reopen the file under process

You state that your I-94 expired on March 17, 2013 and the question is whether the expiration occurred prior to or after the denial of your change of status request from B-2 to F-2. For purposes of the three-year bar for an overstay, that would be if you remained in the US for 180 days or more after the occurrence of the last event – expiration of the I-94 or denial of the change of status request. A motion to reopen does not stay the time after which you would be barred. For example, if your change of status denial occurred on April 1, 2013, the three-year bar for an overstay would begin 180 days after April 1, 2013. If your motion to reopen was still pending close to 180 days, you would have to make the choice of either abandoning the motion and leaving or incurring a three-year bar on entry if you stayed and received a denial. A three-year bar would prevent you from returning to the US once you left. I note that the fact that you are presently illegal automatically invalidates your visitors visa and that you will have to obtain another before reentering the US even if you left at this moment. Whether you are able to obtain another visiting visa in short order would be up to an American consular official. I cannot make a recommendation in your case because I do not know the strength of your motion. I can only tell you of possible consequences dependent upon which option you take. Due to the limitations of the Lawyers.com Forums, Alan Lee, Esq.'s (the "Firm") participation in responding to questions posted herein does not constitute legal advice, nor legal representation of the person or entity posting a question. No Attorney/Client relationship is or shall be construed to be created hereby. The information provided herein by the Firm is general, and requires that the poster obtain specific legal advice from an attorney. The poster shall not rely upon the information provided herein as legal advice nor as the basis for making any decisions of legal consequence.

This is what the regulation says: 8 CFR  103.5(a)(1)(iv) Effect of motion or subsequent application or petition. Unless the Service directs otherwise, the filing of a motion to reopen or reconsider or of a subsequent application or petition does not stay the execution of any decision in a case or extend a previously set departure date.