Convert Imported Text File For Calculations

I have a file with four sheets – File1, File2, Association and LookList. File1&2 are totalled, as is Association sheet but then are checked against each other using the totals. What I need to do is the following (but I am not sure how to do it using macro…)

Step 1 - ‘File1’ Sheet – It all comes in text format. Firstly, convert all of column B=>used range (it may vary to 40k records!) into numbers and total each column.
(I know the principal behind it – have a total variable for ColB, loop through and when it finds >0 then increment buy one and output under the last cell in that column – but I do not know the macro code)

Step 2 - ‘File2’ Sheet – Again, it's in text format. Firstly, convert all of column B=>used range into numbers and total each column(would contain same amount of records
as Step1!) .

Step 3 - ‘Association’ – same steps as for File 1 (again – same number of records).

Step 4 - THEN (and I have NO IDEA how to do this!...) I need to check the File1 & File2 against Association using the lookup and return the Serial number and the Association heading that does not match on a fourth sheet.

The problem is that – for example – Field-1 consists total of more than one column – contains 3 but could contain a total of up to 6 columns! - I understand excel formula ‘vlookup’ but am not sure how to do it when it is a combination of columns and even less when applying it to this! – In fact, for a macro I am not even sure what column format the lookup list should be!