Hello Suhas,
Thank you for visiting Microsoft Community and providing us with the detailed description about the issue.
As per the description, I understand that you want to know when you will get free Windows 10 upgrade for your Sony Vaio E- series.
I certainly understand your concern and will try my best to help you.
To download Windows 10, I would suggest you to refer to the article given below and check if that helps.
Download Windows 10
https://www.microsoft.com/en-us/software-download/windows10
If you wish to perform a clean installation of Windows 10, I would suggest you to refer to the suggestions provided by “Andre Da Costa” replied on January 27, 2015 in the following Microsoft Community link.
How to: Do a clean install of Windows 10
For more information:
I would suggest you to refer to the suggestions provided by “Andre Da Costa” replied on January 22, 2015 in the following Microsoft Community link.
Frequently Asked Questions: Windows 10
I hope this information is helpful.
Please do let us know if you need any further assistance, we will be glad to assist you.
Thank you.
Jayant