Sony Vaio series E downgrade from 8.1 to 7 factory settings

Hello,


I need to reset my Vaio to original factory settings using windows 7 .
I currently have 8.1 running on it and it has crashed completely 4times ever since the 8.1 upgrade. I no longer want 8.1 I hate it it's too unstable.

So please if you can help me get rid of the 8.1 and bring back the windows 7 at original factory settings....I would be so appreciative.