First check that that wifi (in Device Manager > Network adaptors > properties – power management tab) is not set to allow the device to wake the computer.
Have you enabled Media Sharing under Network and Sharing Center? If so try the following:
Open Vaio Control Center > Power Management > Power Options > Advanced > Change plan settings > Change Advanced Power Settings > Expand ‘Multimedia Settings’ > Expand ‘When sharing media’ > For both ‘on battery’ and ‘plugged in’ select ‘Allow the computer to sleep’ – you may find that this is presently set to ‘Allow computer to enter away mode’.
If that is not the problem then examine Scheduled tasks (Device Manager > Administrative Tools > Task Scheduler > expand Task Scheduler Library and all subdirectories) for any program that is allowed to wake the computer to run a task – you will find this option on the ‘Conditions’ tab for each instance.