I finally solved my problem, using this code:
dataGridView1[2, 0].Value = "7:00 - 7:50";<br />
dataGridView1[2, 1].Value = "7:50 - 8:40";<br />
dataGridView1[2, 2].Value = "8:40 - 9:30";<br />
dataGridView1[2, 3].Value = "10:00 - 10:50";<br />
dataGridView1[2, 4].Value = "10:50 - 11:40";<br />
dataGridView1[2, 5].Value = "11:50 - 12:40";<br />
dataGridView1[2, 6].Value = "12:40 - 1:30";<br />
It is similar to the coordinate plane, the first number references the number of column, and the second number references the cell that I want to modify. Now I have a bigger problem, about the same project, I'll post it in a minute. Please Help me with that one, I'm trying to solve it since four hours.