My vaio laptop keeps shutting down on its own for no expected reasons any answer

Unexpected shutdowns are typically associated with heat and/or power problems. They can also be cause by driver issues and even with virus attacks.

What, if anything, has recently changed on your system (prior to this happening)? Second, what model of Sony are you using?

step one should be to blow out the cooler vents. get a compressor or canned air and get the dust/hair out of there.

+1, Make sure your fans are still working and that you have enough ventilation space around your Laptop for airflow.