Delete duplicates from tables

Hi,

I have Tables USERS_Pdt with data coulmns -  Product, UserID, Email, Gender, City, State, .... and Tables USER  with data coulmns -  UserID, Email, Gender, City, State, .... with Unique Non Clustered indexes in UserID and Email.

I have situation like below:

The required result is if the new userID is having the blank email then it will put "unknown " as value in email else  email itself. Now the situation is for the same UserID , I got two records for different products. Below is the required result:

Any help is appreciated.

Thanks,

Rajneet