Notice u/s 142 (1)

Hi,

The assessee had not filed I. T. returns for many years due to non taxable income. On 31-12-12, the assessee  received a notice u/s. 142 (1) for AY 2010-2011, for producing explanation of certain transactions (and not for filing of I T retruns) . No assessment notice u/s 143(2) has been issued and served to the assessee on a prior date

Is this notice valid?

What are the time limits and conditions for issue of a notice u/s. 142 (1)

If the assessee appears and provides explanation to the AO can he u/s 292BB and opther provsisons of the Act take action against the assessee for non filing of returns? What addititinal action can the AO take against the assessee.

In case, if the assessee does not file any reply to the notice received or appears and provides any explanation to the AO, what further action can the AO take against the assessee?

Request you if you could also give case laws to strengthen the case of the assessee in the above matter

Awaiting your reply on the above.

Thanks in advance

CSJ