INNO TROUBLESHOOT - Questions Here

[Logrim]

I have a problem, i want a custom form that when click install button, detect if the game is already installed and ofers unninstall it. I have the custom form made and attached in install button, the form works but allways appears, when game is installed and when not..

my code in the install button is this:

function NextButtonClick(CurPageID: Integer): Boolean;
begin
sndPlaySound(ExpandConstant('{tmp}\click.wav'), $0002);
if RegQueryStringValue(HKLM, 'SOFTWARE\Wow6432Node\Microsoft\Windows\CurrentVer sion\Uninstall\Knights of the Old Republic_is1','UninstallString', Uninstall) then
DetectUnsLabel.Show;
DetectUninsForm.ShowModal;
Uninstall:=RemoveQuotes(Uninstall);
if RadioButton_1.Checked then
begin
if not RadioButton_1.Checked then
Result := True;
end;
end;

EDIT:Another question.. how to hide a custom form?

Thanks, and again sorry if my english is not god.