Calculating Cells in Excel using VB

[eddyys]

Hi
can someone help me out
I have crated a user form with two combo boxes, I am trying to add the values within the range specified in combo box from the excel worksheet, for example the worksheet as column A contains Jan, feb,mar,.....Dec and column B contains 1, 2,3,..... 12, if i select the combobox1 as Feb and combobox 2 as Nov it should sum the values of B column adjacent to feb to apr as 9. i am unable to get this output... can someone help me out

[snb]

I can't open your example workbook.