how 'bout:
usage: txtbox.default = getStartOFWeek(Date())
Code:
'give any date and get the date that starts the week
Public Function getStartOFWeek(ByVal pvDate) As Date
Dim iDow As Integer, iSTARTDAY As Integer
Dim i As Integer
iSTARTDAY = vbFriday
'iSTARTDAY = Range("I2").Value
iDow = Format(pvDate, "w")
Select Case True
Case IsNull(pvDate)
getStartOFWeek = Null
Case iDow = iSTARTDAY
getStartOFWeek = pvDate
Case Else
i = iSTARTDAY - iDow
If i > 0 Then i = i - 7
getStartOFWeek = DateAdd("d", i, pvDate)
End Select
End Function