If you can't adjust signal/monitor settings from taskbar...
Minimize all computer program windows until you get back to your desktop (the screen that is on the computer monitor before you open programs). Click the right mouse button once on any unoccupied place on the desktop. Choose "Properties" from the drop down menu that appears. Choose the "settings" tab in the Properties window.
In the Settings window choose "Advanced." This will open a window that will give you several choices in the form of tabs.
Choose a tab that is not General, Troubleshoot, or Monitor. The exact label will depend upon your computer's video card. Look for a tab that is labeled with your video card's maker's name.
Then under this tab look for properties.
On many notebooks, especially late models, you will have two options:
1. Clone your desktop
2. Extended Desktop
Choose "Clone" if you want the screen on your notebook to be the screen that you are projecting. This is the most often used choice.
Choose "Extended Desktop" if you want to have a screen available that is not being projected. This is a good choice if you want to do some work that you do not want projected while the projection is running. When you open the PowerPoint Program you would size its window and putting the cursor on the blue program bar at the top, keep the left mouse button down and drag the program window right and watch it appear on the projection. Whatever program is on the original desktop will not be projected.
If you do not find the option for clone, you will need to restart your notebook computer with the vga cable connected to the projector. Make sure also that the projector is turned on and the vga feed has been selected. When your notebook boots up, these options will appear. Choose the one best for you.