Select rows where one row meets a condition
If you can handle both products on the same row:

select t1.UserId, t1.ProductId, t1.Status,
       t2.ProductId as otherproduct, t2.Status as otherproductstatus
from MyTable t1
join MyTable t2
  on t1.UserID=t2.UserID
     AND t1.ProductID=100
     AND t2.productID!=100


However with this you'll get all products for a user: