Macro code to show message depends on selection from Combobox/List

Hi,

I have attached the excel sheet, Sheet "A" contains CUG & CUG Verification, Sheet "B" contains Database.
Example:
If user selects "US" in "A2", depending on that Look into perticular user's CUG number in Sheet B, if the cell contains number show message as "CUG Found" in B2
If user selects "UK" in "A2", depending on that Look into perticular user's CUG number in Sheet B, if the cell contains number show message as "CUG Found" in B2.
If user selects "US & UK" in "A2", depending on that Look into perticular user's CUG number in Sheet B, if the cell contains both number show message as "CUG Found" in B2
Otherwise "No CUG Found".

Thanks