Firstly, don't do it like that! Do not concatenate strings to build a SQL command. It leaves you wide open to accidental or deliberate SQL Injection attack which can destroy your entire database. Use Parametrized queries instead.
And second, comma is not a WHERE condition conjunction: you need AND or OR:
DELETE FROM MyTable WHERE columnName1=value AND columnName2=otherValue
Or
DELETE FROM MyTable WHERE columnName1=value ORcolumnName2=otherValue
Finally, you need to execute the command:
Cmd.ExecuteNonQuery()