Code:
Dim LoanAmount As Decimal
        Dim MonthlyPayment As Decimal
        Dim IntrestRate As Decimal
        Dim Counter As Integer
        Dim Balance As Decimal

        lblMsg.Text = ""

        If IsNumeric(txtLoanAmount.Text) Then
            If txtLoanAmount.Text > 0 Then
                If IsNumeric(txtMonthlyRePayment.Text) Then
                    If txtMonthlyRePayment.Text > 0 Then


                        LoanAmount = txtLoanAmount.Text
                        MonthlyPayment = txtMonthlyRePayment.Text
                        IntrestRate = cboIntrestRate.Text
                        Balance = LoanAmount

                        Counter = 1

                        Do While Balance >= 0
 Balance = LoanAmount - MonthlyPayment + (LoanAmount * IntrestRate)

                            LoanAmount = Balance
                            If Balance >= 0 Then
lstPaymentSchedule.Items.Add("Month " & Counter & " Balance is £" & Math.Round(Balance, 2))
                            Else
lstPaymentSchedule.Items.Add("Month " & Counter & " Balance is £0.00")

                            End If
                            Counter += 1
                        Loop

                    Else
                        lblMsg.Text = "Please enter a value bigger then 0"
                    End If
                Else
                    lblMsg.Text = "Please enter a valid Monthly Repaymment"
                End If

            Else
                lblMsg.Text = "Please enter a value greater than 0"
            End If

        Else
            lblMsg.Text = "Please enter a valid Loanamount"
        End If


    End Sub
Then interface is like
Loan amount : ______ (user puts in data)
Monthly repay: ______ (user puts in data)
Intrest rate: ______ (user selects 0.001, 0.002. 0.003. 0.004)

Payment sched:
Month 1 balance =
month 2 balance =

etc

Everything works fine

just got a problem with few amounts e.g

If user puts in

Loan amount: 10000
Month repy: 1
intrest rate: 0.001

program crashes and says

Value was either too large or too small for a Decimal. (Pointing at the Monthly repayment.

ow can i get round dis

Thanks in advance!