How can I search a data in Excel?

My suggestion would be to utilize the DDT.ExcelDriver objects to create access to each Excel sheet/tab. It would possibly look something like this.

var Driver1, Driver2, Value1, Value2;
Driver1 = DDT.ExcelDriver("C:\\myfiles\\myexcel1.xls","Sheet1");
while (!Driver1.EOF()) {
    Value1 = Driver1.Value("Calumn_A");
    Driver2 = DDT.ExcelDriver("C:\\myfiles\\test_data.xls","Sheet1");
    while (!Driver2.EOF()){
        Value2 = Driver2.Value("Calumn1");
        if (Value1 = Value2){
            switch (Value1){
                case "A" : RunTestA();
                           break;
                case "B" : RunTestB();
                           break;
                case "C" : RunTestC();
                           break;
           
            }
        }
        Driver2.Next();
    }
    DDT.CloseDriver(Driver2.Name);
    Driver1.Next();        
}
DDT.CloseDriver(Driver1.Name);

This is untested and is completely off the top of my head. But this is what I would at least start with. The idea is that you are looping through your first file. Each time through the loop, you create a driver accessing your second file and loop through it. Each loop through the second file compares the values. If they are the same, run a script based upon the value in the first file.