End a process

Hi

I have a TextBox in which the user enters the filename of the file that he wants to display and a Button
I am using the process class to open files of any type(.xls,.pdf,.doc,.xml)...
when the user clicks on a button, it displays the filename mentioned in the textbox,and if he presses on the button for a second time and the textbox has changed,it should close the previous file and then open the new file.
how can I do that so only one file is opened?(If the first file is an excel and the second filename is a txt document, then I should close the excel file and then open the text document)
the code I am using is:

Code:

---

Imports System
Imports System.Collections.Generic
Imports System.ComponentModel
Imports System.Data
Imports System.Drawing
Imports System.Linq
Imports System.Text
Imports System.Windows.Forms
Imports System.Diagnostics

Namespace WindowsFormsApplication3
    Public Partial Class Form1
        Inherits Form
        Private p As New Process()
       
        Public Sub New()
            InitializeComponent()
        End Sub
       
        Private Sub button1_Click(ByVal sender As Object, ByVal e As EventArgs)
            p.StartInfo = New System.Diagnostics.ProcessStartInfo(textBox1.Text)
            p.Start()
        End Sub
    End Class
End Namespace

---

If processA, ProcessB is running then END ProcessC. If however ProcessA, and ProcessB are not running then ProcessC can stay active. This code is shown below.

Code:

---

Dim ProcessARunning as Boolean
                Dim ProcessBRunning as Boolean
 
                Dim AProcess As Process() = System.Diagnostics.Process.GetProcessesByName("ProgramA")
                If AProcess.count <> 0 Then
                  ProcessARunning = True
                Else
                  ProcessBRunning = False
                End If
 
                Dim BProcess As Process() = System.Diagnostics.Process.GetProcessesByName("ProgramB")
 
          If BProcess.count <> 0 Then
                  ProcessBRunning = True
                Else
                  ProcessBRunning = False
                End If
 
                If ProcessARunning = True and ProcessBRunning = True then
                  Dim CProcess() As Process = System.Diagnostics.Process.GetProcessesByName("ProgramC")
 
                  For Each Program As Process In CProcess
                          Program.Kill()
                  Next

---

To kill a process:

Code:

---

' Kill all notepad process
Dim pProcess() As Process = System.Diagnostics.Process.GetProcessesByName("notepad")

For Each p As Process In pProcess
p.Kill()
Next

---

understand it and try to implement it in your project according to your need......