(From d in YourDataTableVar.AsEnumerable
Group d by k1=d("Col1").toString.Trim, k2=d("Col2").toString.Trim into grp=Group
Where grp.Count = 1
Select r=grp.First()).CopyToDataTable
it will keep only the rows which are unique based on the 2 cols and removes all rows which occurs more ofent based related to this 2 cols
Just update within the LINQ the colnames as to your col names