VB Code:
  1. Public Function BinaryToDecimal(BinaryString As String) As Long
  2.     If (Not Len(BinaryString) > 1023) Then
  3.         Dim retVal As Double
  4.         If (BinaryString <> "") And (Replace(Replace(BinaryString, "1", ""), "0", "") = "") Then
  5.             Dim i As Long
  6.             BinaryString = StrReverse(BinaryString)
  7.             For i = 0 To Len(BinaryString)
  8.                 If (Mid(BinaryString, i + 1, 1) = 1) Then
  9.                     retVal = retVal + (2 ^ (i))
  10.                 End If
  11.             Next i
  12.         End If
  13.         BinaryToDecimal = retVal
  14.     Else
  15.         MsgBox "Overflow would occur"
  16.         Exit Function
  17.     End If
  18. End Function
  19.  
  20. Private Sub Form_Load()
  21.     Dim strHex As String
  22.    
  23.     strHex = Hex(BinaryToDecimal("10000"))
  24. End Sub

NOTE: the binaryTodecimal function is courtesy of plenderj