maybe you could try this
int columnNumber = 5; //Put your column X number here
for(int i = 0; i < yourDataTable.Rows.Count; i++)
{
if (yourDataTable.Rows[i][columnNumber].ToString() == "TRUE")
{ yourDataTable.Rows[i][columnNumber] = "Yes"; }
else
{ yourDataTable.Rows[i][columnNumber] = "No"; }
}
Hope this helps...