Hi IRoy,

If you hide a column no-one else can see it unless they unhide it. And that means they are reformatting your workbook - which also explains why the format is no longer what you gave them!

However, even if you hide a column it is still possible to select cells in it it (eg via Goto) and see what they contain. To prevent this:
• select the whole of your used range, then choose Format|Cells|Protection and check the 'hidden' option (the 'locked' option should already be checked)
• hide any rows/columns you don't want the users to be able to access - including rows/columns outside the used range.


• select the cells you want the users to be able to see and choose Format|Cells|Protection and uncheck the 'hidden' option for those cells only.
• select the cells you want the users to be able to edit and choose Format|Cells|Protection and uncheck the 'hidden' and 'locked' options for those cells only.
• choose Format|Protect Sheet and uncheck 'select locked cells'. You might also want to apply some of the other protection options. Then apply a password to your worksheet.

__________________
Cheers,
Paul Edstein
[Fmr MS MVP - Word]