DirectX setup works but doesn't show dialog with progress in XP (in win 2K all is OK)

I am using in my installer a call to DirectXSetup in DSETUP.dll to install DirectX if it is necessary. All works fine in win 2k and a dilog window with progress bar for DirectX files is shown, but in win XP dialog window does not appear. Nevertheless DirectX setup takes place.

This is the call I have

System::Call 'DSetup:😁irectXSetup(i, t, i) i \

($HWNDPARENT, "$WINDIR\temp\DX2005Redist", ${DSETUP_DIRECTX}) .r0'

StrCmp $0 ${DSETUPERR_SUCCESS} done

StrCmp $0 ${DSETUPERR_SUCCESS_RESTART} 0 error

...

Any suggestion?

Doesn't DirectX 9 come preloaded with Windows XP? If it's already installed, no installation should take place and so no dialog should appear.

Thanks for replying. I was waiting for any reply desperatly.

I need to detect if last version of DirectX is installed (June 2005 Edition). The problem is that in Win2k I get the microsoft progress dialog during DirectX setup when I make the call:

System::Call 'DSetup:😁irectXSetupA(i, t, i) i \
$HWNDPARENT, "$WINDIR\temp\DX2005Redist", ${DSETUP_DIRECTX}) .r0'

In WinXP the setup takes places but no dialog appears.

I have chequed HWNDPARENT and it is 0 because before I make the call I destroy a banner I have. But anyway this must not be the reason because in this case the microsoft dialog must take as parent the desktop windows.

I can't understand the reason why installer behaves different in Win XP