How to return a list of software installed on a computer?

Well you can loop through c:\program files and see the current applications

It is impossible to list ALL software on a system.

You could certainly determine what programs are listed in the Add/Remove section of the conrol panel but that is not always accurate as sometimes applications get orphaned there even though they were uninstalled long ago.

Additionally, not all programs on a system are listed there.  Any app that doesn't require installation will simply reside on the hard drive somewhere, and not necessarily in the "Program Files" folder either.

With that info in mind...you can duplicate the Add/Remove list by going to this key in the registry:

    HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\Uninstall

Then simply enumerate all the entries and fetch the DisplayName value from each one.

Regards,

Idle_Mind

Here is an example of enumerating the Uninstall key and placing the list into a ListBox:

Imports Microsoft.Win32

Public Class Form1
    Inherits System.Windows.Forms.Form

#Region " Windows Form Designer generated code "

    Public Sub New()
        MyBase.New()

        'This call is required by the Windows Form Designer.
        InitializeComponent()

        'Add any initialization after the InitializeComponent() call

    End Sub

    'Form overrides dispose to clean up the component list.
    Protected Overloads Overrides Sub Dispose(ByVal disposing As Boolean)
        If disposing Then
            If Not (components Is Nothing) Then
                components.Dispose()
            End If
        End If
        MyBase.Dispose(disposing)
    End Sub

    'Required by the Windows Form Designer
    Private components As System.ComponentModel.IContainer

    'NOTE: The following procedure is required by the Windows Form Designer
    'It can be modified using the Windows Form Designer.  
    'Do not modify it using the code editor.
    Friend WithEvents ListBox1 As System.Windows.Forms.ListBox
    <System.Diagnostics.DebuggerStepThrough()> Private Sub InitializeComponent()
        Me.ListBox1 = New System.Windows.Forms.ListBox
        Me.SuspendLayout()
        '
        'ListBox1
        '
        Me.ListBox1.Anchor = CType((((System.Windows.Forms.AnchorStyles.Top Or System.Windows.Forms.AnchorStyles.Bottom) _
                    Or System.Windows.Forms.AnchorStyles.Left) _
                    Or System.Windows.Forms.AnchorStyles.Right), System.Windows.Forms.AnchorStyles)
        Me.ListBox1.Location = New System.Drawing.Point(8, 8)
        Me.ListBox1.Name = "ListBox1"
        Me.ListBox1.Size = New System.Drawing.Size(432, 277)
        Me.ListBox1.TabIndex = 0
        '
        'Form1
        '
        Me.AutoScaleBaseSize = New System.Drawing.Size(5, 13)
        Me.ClientSize = New System.Drawing.Size(448, 294)
        Me.Controls.Add(Me.ListBox1)
        Me.Name = "Form1"
        Me.Text = "Add/Remove Program Listing"
        Me.ResumeLayout(False)

    End Sub

#End Region

    Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
        Try
            Dim rk As RegistryKey = Registry.LocalMachine.OpenSubKey("Software\Microsoft\Windows\CurrentVersion\Uninstall")
            Dim sk As String
            Dim appKey As RegistryKey
            Dim displayNameValue As Object
            Dim displayName As String
            ListBox1.Sorted = True
            If Not (rk Is Nothing) Then
                For Each sk In rk.GetSubKeyNames
                    appKey = rk.OpenSubKey(sk)
                    displayNameValue = appKey.GetValue("DisplayName")
                    If Not (displayNameValue Is Nothing) Then
                        ListBox1.Items.Add(CType(displayNameValue, String))
                    End If
                Next
            End If
        Catch ex As Exception
            MsgBox(ex.Message, MsgBoxStyle.Information, "Error Accessing Registry")
        End Try
    End Sub
End Class