Problem to creating a calander

[Rocky2013]

Hi,
I try to setup one calender, then use validation list for year and month.
Then I use vlookup to find year and month then look for JanSun1 in cell B10.
So B10=JanSun1

Below is the working orginal formula to find the date on Sunday in January;
The result is a blank.
=IF(AND(YEAR(JanSun1)=$A$1,MONTH(JanSun1)=1),JanSun1, "")

Once JanSun1 is substituted with B1,the formula does not work.
=IF(AND(YEAR(B10)=$A$1,MONTH(B10)=1),B10, "")

I press F9 to see B10, which shows "JanSun1" with quotation marks.
I use value(B10) try to elimate the quotation mark, it does not work.

Please advise. Thanks

[Tsjallie]

Let me guess
B10 should contain

=JanSun1