which is better ADO.NET or Sql to Linq in c# windows project

Actually Linq depends on ADO.Net but, it's better to use LINQ becacuse you don't need to write a lot of queries as well as creating a database then writing the coressponging C# classes, If you use, you only should build the database and the classes will be ready for you, also it's very easy to deal with database using LINQ because it's very flexible as well as it implements the OOP term, so you'r working with the records as an objects.

You don't need to waste a lot of time with Writing SQL Queries with ADO.Net Linq will do this for you.