Macros can do many things.....write to the registry, delete and change files and
all kinds of neat things.

You can bugger up your computer easily by running a macro with malicious code in
it.

The ones you write yourself can only do what you have written. What they can do
is up to you.

To protect yourself, don't download files that contain macros unless you trust
the source or the macros have a signed digital certificate.

Always have your macro security at Medium or higher.

To get away from the security warning on your own workbooks with macros, you can
use the SelfCert tool to digitally sign your own workbooks for use on your
computer only.


Gord Dibben MS Excel MVP

On Fri, 12 Oct 2007 14:18:01 -0700, peyman
wrote:

HI,
how a macro can contain viruses!!???even the ones I write myself and post it
in my worksheets!!?or the macros I get from websites or something?what's the
solution to protect the files?
thanx