Convert to CSV produce different result

I'm using MS Excel 2003 on Windows XP Pro and my friend is using the same thing on Pentium 4 and I'm using the same machine except that mine is a laptop and hers is a desktop.

We converted an Excel file to csv, close the file and open it again using Excel..

Mine looks like normal Excel. But hers, each column is separated by a semi-colon, like this

No.;Staff No.;Name;Year-mth;AmountDue;AmountPd;Reason
1;10009140;Mohd.Said B.Ahmad Ichock;2008-04; 4.00 ; 4.00 ;
2;10009171;Sahar B.Mohd.Nawi;2008-04; 4.00 ; 4.00 ;
3;10009193;Salim B.Mohamad;2008-04; 4.00 ; 0.00 ;20/50

We need it to be looking just like Excel since our system do not understand the semi-colon as a field separator

Appreciate if anybody can tell us, what is lacking. I think there must be due to a missing dll but I'm not sure what and where to put