There is no sqrt key on the scientific calculator, only on standard. You have to use the x^y operation with the second operand .5 For example, 16 [x^y].5= 4 , or use Inv x^y such as 16 Inv x^y 2 = 4
Or download Microsoft Mathematics
http://www.microsoft.com/download/en/details.aspx?id=15702
That's a really nice calculator.