ATI graphics driver fails to install

 I tried to install a driver (which worked under WinXP) for the ATI Mobility Radeon 2600 on my HP Compaq 8510p. Even with MFC42.dll in system32 folder the setup failed right at the start.

An unzipped driver installer offers several executables which I tried. Here are the results without compatibility mode:

• Setup.exe -> "Setup konnte die Installation nicht starten (0x80040707) (aka "Setup could not start installation")
• issetup.exe -> Same result as above (gets started by setup.exe obviously)
• Driver\Setup.exe (video driver setup itself) -> Shows welcome screen, then shows error dialog: "Es wurde kein Treiber gefunden, der mit der aktuellen Hardware oder dem Betriebssystem kompatibel ist. Setup wird beendet." (engl.: Found no driver which is compatible with current hardware or OS. Setup is cancelled.")

With WinXP SP3 compatibility mode:

• Setup.exe ->Shows only light blue fullscreen installer window, nothing more happens.
• issetup.exe -> Same result as above (as expected)
• Driver\Setup.exe (video driver setup itself) -> Same as without compatibility mode, that is, error about no suiable driver found.