You can use your 'Scheduled Tasks' to run a cron. --- In your System Tools area.
Here is a code to run in the morning via Scheduled tasks, or whenever you don't want access. Just save as deny.vbs somewhere. You may have to edit the 'hosts' location.
Code:
Set fso_obj = CreateObject("Scripting.FileSystemObject")
fso_obj.CopyFile "C:\WINDOWS\system32\drivers\etc\denyhosts", "C:\WINDOWS\system32\drivers\etc\hosts"
now save this code as allow.vbs and use Scheduled Tasks to turn your access back on .
Code:
Set fso_obj = CreateObject("Scripting.FileSystemObject")
fso_obj.CopyFile "C:\WINDOWS\system32\drivers\etc\allowhosts", "C:\WINDOWS\system32\drivers\etc\hosts"
Now to use the above you will need 2 versions of your hosts file. You can call one 'denyhosts', and the other 'allowhosts'. You can save them in the same place you saved the vbs files, or with your existing hosts file(the way the code above shows), just change the locations to match.