My desktop was having issues updating to Windows XP Professional SP2. And when it failed and couldn't restore, I couldn't boot up the computer. So I used a Windows XP Professional SP3 CD to repair install. Everything was fixed, except for two things. When I click Start, then to Log Off or Turn Off Computer, the mouse cursor turns into one of those hour glasses and the desktop freezes. That's minor, because all I had to do was create a Shutdown shortcut. But when I tried to uninstall Norton, the computer said Windows Installer may not be installed correctly. So I googled it, and I tried to uninstall/reinstall Windows Installer. When I install, the message Access is Denied appears, and the Uninstaller shows up. How do I install Windows Installer?