Open the Adobe Reader download page in Opera (see Resources) and download the installer to your computer by clicking "Download Now."
Close all open Opera windows.
Double-click the downloaded Adobe Reader installer EXE file on your computer and install it by following the instructions on your screen.
Open Opera by clicking "Start," "All Programs" and "Opera."
Click the "Tools" menu and choose "Preferences."
Click the "Advanced" tab at the top of the "Preferences" window and click "Downloads" at the left side of the window.
Click "application/pdf" in the list of file types and click "Edit."
Click "Use Plug-in" at the bottom of the "File Type" window and click "OK" twice.