Hello,
MMnnn...If UAC is enabled, the program should prompt for an elevation and ask you to authenticate as administrator.
Go to
Control Panel >
User Account >
User Accounts.
(The exact location to this in explorer is
Control Panel\User Accounts\User Accounts)
Click on
Turn User Account control on or off. Is UAC on or off?
Go back to the User Accounts page. Click
Change your account type. You should see the options 'Standard user' and 'Administrator'. Is 'Administrator' checked? If not, check it, then click on the 'Change Account Type' button and try installting the application again.