Insstalling either Windows 2000 SP4 or SP3 on my Windows 2000 SP2 HP Omni 900 notebook results in error that the Windows Installer is not digitally signed. Clicking the "OK" button results in "An unexpected error occured" and the setup fails. Thinking maybe it's an oudated Windows Installer - "Msiexec.exe" is the cause, installing Windows Installer 3.1 Redistributable (v2) results in error saying it needs SP3 and thus also fails. Downloading from Microsoft SP4, SP3 sites, saving it on my notebook and then executing them results in "SP4 (or SP3) Setup determined that the following downloaded SP4 (or SP3) files are corrupt"- showing a whole list of them. Please help. Thanks.
