Homework Problem?? *RESOLVED*

[twisted]

Here is what I have to build:
Checking Account
I am stuck on my Withdrawal values and Balance. I think I can figure out Balance if I can get my Withdrawals to work correct. Withdrawals is just the Transaction Amount when radio button Check is checked. I have it represented as WT = WT + TA.

My problem is TA is retaining it's value everytime I click anything. I have it as TA = Val(txtTransaction.Text).

When I type 300 in TA and have the radio Deposit checked, then everything works fine. My txtDeposits.Text displays right and so does txtBalance.Text, but when I click Next and reset TA, and check radio Check, then somehow it it using the value I entered before and then calculating Withdrawals. I think it might be the way I have set up the variables but really don't know. This is the code I have:

Option Strict On
Public Class Form1
    Inherits System.Windows.Forms.Form
 
    ' Assignment 3:     Checking Account
    ' Programmer:       Brad von Oven
    ' Date:             June 12, 2004
    ' Purpose:          Create an application to display a checkbook.  
    '                   The user enters a transaction amount in a text 
    '                   box and selects a button for deposit or check.  
    '                   An update button performs validation on the text 
    '                   box to make sure there is a number greater 
    '                   than 0 in the box.  If the entry is not OK then 
    '                   use a message box to tell the user and reset the 
    '                   focus back to the text box and stop the sub 
    '                   procedure.  When the entry is acceptable the 
    '                   update button evaluates the transaction and 
    '                   adds deposits while subtracting checks from the 
    '                   balance.  If the check is greater than the 
    '                   balance a service charge of $25 is applied 
    '                   instead of the check amount.  Keep track of the 
    '                   balance, total amount in dollars of checks, 
    '                   deposits and service charges.  Display the 
    '                   results.  Option strict is on.
 
    ' Declare variables and constants
    Dim TA, BL, WT, CH, DP, DX As Double
    Const CA As Double = 25
    ' TA is txtTransaction
    ' BL is txtBalance
    ' WT is txtWithdrawals
    ' CH is txtCharges
    ' DP is txtDeposits
    ' CA is Charge Amount
 
 
    Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
 
    End Sub
 
    Private Sub btnNext_Click(ByVal sender As Object, ByVal e As System.EventArgs) Handles btnNext.Click
        txtTransaction.Text = ""
        txtTransaction.Focus()
    End Sub
 
    Private Sub btnUpdate_Click(ByVal sender As Object, ByVal e As System.EventArgs) Handles btnUpdate.Click
        TA = Val(txtTransaction.Text)
        DP = DP + TA
        DX = DP
        WT = WT + TA
        CH = CH + CA
        BL = ((DX - TA) - WT)
        
        If txtTransaction.Text <= "0" Then
            MessageBox.Show("Please enter an amount > 0.", "Error")
            txtTransaction.Focus()
        End If
 
 
        If radDeposit.Checked Then
            txtDeposits.Text = (DP).ToString("c")
            txtBalance.Text = (DP).ToString("c")
 
        End If
        
        If radCheck.Checked Then
            txtWithdrawals.Text = (WT).ToString("c")
            txtBalance.Text = (BL).ToString("c")
        End If
 
    End Sub
End Class