Compare 2 Workbooks and Highlight Differences

I have an excel document that I get each week with a list of all order requests from a customer.

Columns are as follows
PO#, Material, Description, Delivery Date, Qty, Customer Comment

Each week the new excel sheet may have delivery date changes or qty changes for a PO# or a line may have been deleted.

What I would like to do is have a fairly simple way to compare each sheet whether with a function or some programming that would highlight whether any cell has been changed in each row or somehow show whether a line has been deleted or added.
The problem I am having is there is no unique identifier for each row.
The PO# may be in multiple times.

Any ideas on how I could go about this? I don't know VBA that well.
I am using Excel 2007. I have another user on Excel 2003 that would benefit with a solution on this as well.

There is a similar post here, only I need to detect row deletions AND additions

Any help would be very helpful!

Regards,

LM