Hi DHJ,
Welcome to VBAX.
Adapting your code, try the following. If you want to post a sample of your workbook and code, you can do this by zipping the file and using the Manage Attachments button when you use the Go Advanced option. You can also format your code by selecting it and clicking on the VBA button.
Sub Test()
Dim cCustName As Range
Dim CurrentRow As Integer
Const cSiteNotes As Integer = 17
Set cCustName = Sheets("Sheet1").Cells(9, 4)
CurrentRow = 1
If IsEmpty(cCustName) Then
PromptForName
End If
If IsEmpty(Sheets("sheet3").Cells(CurrentRow, cSiteNotes)) Then
PromptForSite
End If
End Sub
Sub PromptForName()
MsgBox "give me a name"
End Sub
Sub PromptForSite()
MsgBox "give me a site"
End Sub