It is probably because you have missing single quotes i.e. this line
OleDbCommand cm=new OleDbCommand("UPDATE qq SET ahmed='"+textBox1.Text+"',ali="+textBox2.Text+",NOTE='"+textBox3.Text+"' WHERE ID="+comboBox1.Text,cn);
Should be written like this
OleDbCommand cm=new OleDbCommand("UPDATE qq SET ahmed='"+textBox1.Text+"',ali='"+textBox2.Text+"',NOTE='"+textBox3.Text+"' WHERE ID="+comboBox1.Text,cn);
you missed the single quotes around
textBox2.Text
Please, let me know if this solves your problem :) .