No,you don’t as in that time you were not a muslim. http://www.youtube.com/watch?v=dPNIZWKrvC8

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If you remember it soon after the salah, you must offer it. but if you remember it after leaving the masjid or after a long gap, your prayer is correct but there is nothing else to do.

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You should stand and offer ruku which you are in doubt of and then offer prostration of forgetfulness after the salam and offer another salam.

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