Inno - install .Net Framework and vb.net application

Hey,

I have a couple questions about using Inno. I currently have code to install my vb.net application. But I want the installer to check to see if the .net framework is already installed, and if it isn't, install it.

Here's the code I have:

Code:

---

; Script generated by the Inno Setup Script Wizard.
; SEE THE DOCUMENTATION FOR DETAILS ON CREATING INNO SETUP SCRIPT FILES!

[Setup]
; NOTE: The value of AppId uniquely identifies this application.
; Do not use the same AppId value in installers for other applications.
; (To generate a new GUID, click Tools | Generate GUID inside the IDE.)
AppId={{0036A914-C4A3-4165-BB3A-E68C78B495CF}
AppName=Contacts
AppVerName=Contacts Beta
DefaultDirName={pf}\Contacts
DefaultGroupName=Contacts
DisableProgramGroupPage=yes
OutputBaseFilename=setup
Compression=lzma
SolidCompression=yes

[Languages]
Name: "english"; MessagesFile: "compiler:Default.isl"

[Tasks]
Name: "desktopicon"; Description: "{cm:CreateDesktopIcon}"; GroupDescription: "{cm:AdditionalIcons}"; Flags: unchecked
Name: "quicklaunchicon"; Description: "{cm:CreateQuickLaunchIcon}"; GroupDescription: "{cm:AdditionalIcons}"; Flags: unchecked

[Files]
Source: "E:\Desktop\setup\contacts.exe"; DestDir: "{app}"; Flags: ignoreversion
Source: "E:\Desktop\setup\data\*"; DestDir: "{app}"; Flags: ignoreversion recursesubdirs createallsubdirs
; NOTE: Don't use "Flags: ignoreversion" on any shared system files

[Icons]
Name: "{group}\Contacts"; Filename: "{app}\contacts.exe"
Name: "{group}\{cm:UninstallProgram,Contacts}"; Filename: "{uninstallexe}"
Name: "{commondesktop}\Contacts"; Filename: "{app}\contacts.exe"; Tasks: desktopicon
Name: "{userappdata}\Microsoft\Internet Explorer\Quick Launch\Contacts"; Filename: "{app}\contacts.exe"; Tasks: quicklaunchicon

[Run]
Filename: "{app}\contacts.exe"; Description: "{cm:LaunchProgram,Contacts}"; Flags: nowait postinstall skipifsilent

---

Thanks in advance!