Running scripts in C#

check with this sample

http://support.microsoft.com/kb/306683

using Excel = Microsoft.Office.Interop.Excel;  //(Add Reference - COM Tab - Microsoft Excel 12.0 Object Library)
using System.Reflection;  // Excel
using System.Data.OleDb;  // Reading Excel
.....
Excel.Application excelApp;
Excel._Workbook excelWB;
Excel._Worksheet excelSheet;
Excel.Range oRng;

        private void button1_Click(object sender, EventArgs e)
        {

            try
            {
                //Start Excel and get Application object.
                excelApp = new Excel.Application();
                excelApp.Visible = false;

                //Get a new workbook.
                excelWB = (Excel._Workbook)(excelApp.Workbooks.Add(Missing.Value));
                excelSheet = (Excel._Worksheet)excelWB.ActiveSheet;

                //Add table headers going cell by cell.
                excelSheet.Cells[1, 1] = "First Name";
                excelSheet.Cells[1, 2] = "Last Name";
                excelSheet.Cells[1, 3] = "Full Name";
                excelSheet.Cells[1, 4] = "Salary";

                //Format A1:D1 as bold, vertical alignment = center.
                excelSheet.get_Range("A1", "D1").Font.Bold = true;
                excelSheet.get_Range("A1", "D1").VerticalAlignment =
                    Excel.XlVAlign.xlVAlignCenter;

                // Create an array to multiple values at once.
                string[,] saNames = new string[5, 2];

                saNames[0, 0] = "John";
                saNames[0, 1] = "Smith";
                saNames[1, 0] = "Tom";
                saNames[1, 1] = "Brown";
                saNames[2, 0] = "Sue";
                saNames[2, 1] = "Thomas";
                saNames[3, 0] = "Jane";
                saNames[3, 1] = "Jones";
                saNames[4, 0] = "Adam";
                saNames[4, 1] = "Johnson";

                //Fill A2:B6 with an array of values (First and Last Names).
                excelSheet.get_Range("A2", "B6").Value2 = saNames;

                //Fill C2:C6 with a relative formula (=A2 & " " & B2).
                oRng = excelSheet.get_Range("C2", "C6");
                oRng.Formula = "=A2 & \" \" & B2";

                //Fill D2:D6 with a formula(=RAND()*100000) and apply format.
                oRng = excelSheet.get_Range("D2", "D6");
                oRng.Formula = "=RAND()*100000";
                oRng.NumberFormat = "$0.00";

                //AutoFit columns A:D.
                oRng = excelSheet.get_Range("A1", "D1");
                oRng.EntireColumn.AutoFit();

                //Make sure Excel is visible and give the user control
                //of Microsoft Excel's lifetime.
                excelApp.Visible = false;
                excelApp.UserControl = false;
                excelWB.Close(true, "C:\\CSharp\\Windows\\CalcGain\\Test1.xlsx", false);
            }
            catch (Exception theException)
            {
                String errorMessage;
                errorMessage = "Error: ";
                errorMessage = String.Concat(errorMessage, theException.Message);
                errorMessage = String.Concat(errorMessage, " Line: ");
                errorMessage = String.Concat(errorMessage, theException.Source);

                MessageBox.Show(errorMessage, "Error");
            }
        }

HTH
Ashok