How to disable Back Button if it selects any records from Grid View

Question

private void btnBack_Click(object sender, EventArgs e)

{

//if(Convert.ToString(dgvCollateralSearchAccountResults.SelectedRows[0].Cells[0].Value)

this.Hide();

CollateralWelcome CW = new CollateralWelcome();

CW.Show();

//pnlSearchResults.Show();

//pnlSearch.Show();

}

 

With this piece of code I am able to go back but one condition is there like if user select any records from  

dgvCollateralSearchAccountResults ,Back Button should be disabled.

 

Please suggest me