If your virtual machine won't run after you update your VirtualBox and you get the error, “Result Code: E_FAIL (8x0004005),” it's most likely you just forgot to also update the extension plug-in. (Sometimes a VirtualBox update will automatically prompt for also installing the extensions, but sometimes it doesn't.) The version numbers of VirtualBox and the extension plug-in must match!
On the page where you download VirtualBox, you should also find a link to download the “VirtualBox Extension Pack.”
If you need to install an extension pack for an older version of VirtualBox, scroll down a bit on the download page and you'll find a link to “Previous Releases, VirtualBox older builds.”