UPDATE query syntax error in vb.net using mysql

Here is a better way to build this query:

str = "update student " &
        " set course= @course, name= @name, f_name= @fname, address= @address," & 
        " tel_no= @tel, qualification = @qualification, remarks= @remarks," & 
        " `school/college`=@school, fee= @fee" &
      " where reg_no= @regno"

Using cn  As New MySqlConnection("connection string here"), _
      cmd As New MySqlCommand(str, cn)

    'Use actual column types/lengths from your DB here
    cmd.Parameters.Add("@course", MySqlDbType.VarChar, 15).Value = ComboBox1.Text
    cmd.Parameters.Add("@name", MySqlDbType.VarChar, 25).Value = TextBox2.Text
    cmd.Parameters.Add("@fname", MySqlDbtype.VarChar, 25).Value = TextBox3.Text
    cmd.Parameters.Add("@address", MySqlDbType.VarChar, 120).Value = TextBox4.Text
    cmd.Parameters.Add("@tel", MySqlDbType.VarChar, 25).Value = TextBox5.Text
    cmd.Parameters.Add("@qualification", MySqlDbType.VarChar, 40).Value = TextBox6.Text
    cmd.Parameters.Add("@remarks", MySqlDbType.VarString).Value = TextBox7.Text
    cmd.Parameters.Add("@school", MySqlDbType.VarChar, 40).Value = TextBox8.Text
    cmd.Parameters.Add("@fee", MySqlDbType.Decimal, 6, 2).Value = Convert.ToDecimal(TextBox10.Text)
    cmd.Parameters.Add("@regno", MySqlDbType.Int32).Value = Integer.Parse(TextBox9.Text)

    cn.Open()
    cmd.ExecuteNonQuery()
End Using

This does a number of things for you:

1. It prevents sql injection attacks
2. It allows you to accept data that includes things like single quotes ('). The code you have will fail if someone puts in a single quote.
3. It handles things like date formatting for the sql automatically.
4. It's faster, because the database server can cache the execution plan after it compiles the query, and use statistics over time to get better execution plans.
5. It closes the db connection more reliably. The current code leaves the database connection hanging open if an exception is thrown.