Sum data from all workbooks

Hi guys,

i'm very new to vba and thus would appreciate any advice from you guys on this. There are several workbooks in 1 folder, all containing 1 spreadsheet per workbook. Lets say e.g. each workbook represents a salesperson's sales record over a period of time. The format within each spreadsheet is the same e.g. 4 columns:
- 1st column containing sequence of dates,
- 2nd column contains revenue recorded for each date,
- 3rd column - expenses,
- 4th - profit/loss (derived from 2nd column - 3rd column).
The idea is to consolidate these into a master workbook that sums up all the data for all salespersons each day. In addition, the master workbook would have a 5th column that counts the number of salespeople who made a profit each day (if there are 5 salesmen with a positive number in the 4th column on day1, then this cell value should be 5) and a 6th column that counts number who made a loss each day (the inverse of 5th column).
Thank u for any help in advance!

Forgot to mention the version i'm on is excel 2007. thanks