My guess is your mouse is switched to left-handed mode (or turned off of
left-handed mode if that is how you usually use it. To check this,
double-click one of those icons with the other mouse button. If that acts
like your normal button used to, do the following.
Go to Start -> Control Panel -> Mouse
If the "Swap left and right button functions of USB mouse" is checked,
uncheck it.
If it is not checked but you use the mouse as a left-handed mouse, check it.
If it is unchecked but and you use it as a normal right-handed mouse, make
sure the "Left Button" is set to Click and the "Right Button" is set to
Shortcut Menu.
Good luck.