// Prompt the user for service installation account values.
public static bool GetServiceAccount(ref ServiceProcessInstaller svcInst)
{
    bool accountSet = false;
    ServiceInstallerDialog svcDialog = new ServiceInstallerDialog();

    // Query the user for the service account type.
    do
    {
        svcDialog.TopMost = true;
        svcDialog.ShowDialog();

        if (svcDialog.Result == ServiceInstallerDialogResult.OK)
        {
            // Do a very simple validation on the user
            // input.  Check to see whether the user name
            // or password is blank.

            if ((svcDialog.Username.Length > 0) &&
                (svcDialog.Password.Length > 0)   )
            {
                // Use the account and password.
                accountSet = true;

                svcInst.Account = ServiceAccount.User;
                svcInst.Username = svcDialog.Username;
                svcInst.Password = svcDialog.Password;
            }
        }
        else if (svcDialog.Result == ServiceInstallerDialogResult.UseSystem)
        {
            svcInst.Account = ServiceAccount.LocalSystem;
            svcInst.Username = null;
            svcInst.Password = null;
            accountSet  = true;
        }
            
        if (!accountSet )
        {
            // Display a message box.  Tell the user to
            // enter a valid user and password, or cancel
            // out to leave the service account alone.
            DialogResult result;
            result = MessageBox.Show("Invalid user name or password for service installation."+
                                     "  Press Cancel to leave the service account unchanged.",
                                     "Change Service Account", 
                                     MessageBoxButtons.OKCancel,
                                     MessageBoxIcon.Hand);

            if (result == DialogResult.Cancel)
            {
                // Break out of loop.
                break;
            }
        }
    } while (!accountSet);

    return accountSet;
}