sql = "INSERT INTO Cars ([Desc]) VALUES('" + sName + "') ";
The column name "Desc" is a bad selection: DESC is a keyword in most (or even all!) sql dialects ("order by column1 desc"). With MS SQL Server or MS Access, you can use it when you put it in square brackets [].
Also note the the name must not contain a
'
character with this simple version of creating the query. Better change to parameterized queries.