Excel Not formatting a file correctly

I am using Excel 2003
I have the column separator set to Tab Delimited
I'm opening a .xls file, which was created from an application coded in vb.net and it's just a few records with 10 columns that are all separated by a Tab.

When i create it and open it in note pad it is fine, all spaced out, with tabs.
When i open it with excel it's all in one column, when i go to change the Deliminator in the data file menu, it is already set to Tab and i just click finish and it formats the file data correctly then and the columns are all separate again...

Does anyone have any thoughts and solutions to my problem please?

I have tried opening the file on multiple computers and some other computers have the same problem as me and others don't it works fine for them.. all tests have been on excel 2003.