This vid helps Fix Error Code 0x12465ad0 (aka, "The instruction at 0x12465ad0 referenced memory at 0x12465ad0. The memory could not be written") while trying to run VirtualBox on Windows.
1. Temporarily uninstall any other 3rd-party security program like McAfee using the recommended uninstall tool in this video > restart when ready > reinstall your AV later. 2. Uninstall current/OLD VirtualBox (ex, 4.3.20) > restart when ready > install the latest version of VirtualBox. More, update your video driver.