Couldn't figure out the VirtualBox(Ubuntu) problem

I used Ubuntu by Virtual Box but suddenly not working with below error messages:

The virtual machine 'Ubuntu' has terminated unexpectedly during startup with exit code -1073741819 (0xc0000005). 
More details may be available in 'C:\Users\asuspc\Desktop\ubuntu\Ubuntu\Logs\VBoxHardening.log'.

Couldn't figure out what is the problem. Please help me

This looks like a hardening issue with your virtualbox. Hardening was introduced to guard against the possibility that malware running on the HOST could inject a DLL into a VM which could then run at elevated privileges (hiding behind Oracle certification) which would be denied to it if it were to run stand alone.

You can check the log file to see further details about the failure or you can see Diagnosing hardening issues.