On Windows 8.0, VT-x suddenly enabled and in a VirtualBox virtual machine it suddenly stopped working after this

This is the error:

Failed to open a session for the virtual machine Windows 7.
The virtual machine 'Windows 7' has terminated unexpectedly during startup with exit code 1 (0x1). More details may be available in 'C:\Users\user\VirtualBox VMs\Windows 7\Logs\VBoxHardening.log'.

Result Code: E_FAIL (0x80004005)
Component: MachineWrap
Interface: IMachine {5047460a-265d-4538-b23e-ddba5fb84976}

Don't know what any of it means, but I would appreciate an answer.