try this:
Code:
Option Explicit

Dim intNext As Long

Private Sub Command1_Click()
    Dim I As Long, dblSum As Double
    Dim strWar As String
    Dim bOK As Boolean
    
    ' you should have some error handling here,
    ' but i'll leave that for you to do
    intNext = CLng(Text2.Text)
    
    For I = 0 To intNext
        bOK = False
        Do Until bOK
            strWar = InputBox("Added " & I + 1 & " value", "Adding sections")
            If StrPtr(strWar) = 0 Then
                ' Cancel Pressed
                If dblSum > 0 Then
                    If MsgBox("Do you want to Quit?", vbYesNo _
                        Or vbQuestion, "Question") = vbYes Then Exit Sub
                Else
                    Exit Sub
                End If
            Else
                ' Ok Pressed
                If Not IsNumeric(strWar) Then
                    MsgBox "Enter a correct value!", vbCritical
                Else
                    dblSum = dblSum + CDbl(strWar)
                    bOK = True
                End If
            End If
        Loop
    Next I
    
    MsgBox dblSum
End Sub
avoid using GoTo like the plague