vlookup displays "0" if reference cell is blank?

I am trying to use vlookup so that when each site name is selected the relevant comments for that site are displayed.

I have a formula that is working, but it displays "0" if there is nothing in the cell. How do i get it to display a blank cell if thre is nothing in the reference cell.

this is the formula that i am using:

=IF($C$4="", "", IF($C$4="No Match", "", (VLOOKUP($C$4,Comments!$A$2:$U$295, 5,0))))

The site name appears in C4, and is selected from another sheet in the workbook.