Welcome to the Board!
How about this:
<font face=Tahoma><SPAN style="color:#00007F">Sub</SPAN> FillBlanks()
<SPAN style="color:#00007F">Dim</SPAN> c <SPAN style="color:#00007F">As</SPAN> Range
<SPAN style="color:#00007F">Dim</SPAN> x <SPAN style="color:#00007F">As</SPAN> <SPAN style="color:#00007F">Variant</SPAN>
x = InputBox("What do you want to replace blanks with?", "Replace Item")
<SPAN style="color:#00007F">For</SPAN> <SPAN style="color:#00007F">Each</SPAN> c <SPAN style="color:#00007F">In</SPAN> Selection
<SPAN style="color:#00007F">If</SPAN> c = "" <SPAN style="color:#00007F">Then</SPAN> c = x
<SPAN style="color:#00007F">Next</SPAN> c
<SPAN style="color:#00007F">End</SPAN> <SPAN style="color:#00007F">Sub</SPAN>
</FONT>
Hope that helps,
Smitty