Right-click on Opera and Chrome's desktop shortcut and goto "Properties". Then, on the Shortcut tab, check the target field command to see if anything is being like a bing URL is being passed to opera.exe/chrome.exe. If so, edit the target field so that only the quoted path to opera.exe is in there.
Then, repeat for Opera and Chrome's taskbar button. Right-click on the taskbar button, right-click on "Opera Browser" and then goto properties.