Judy
Since we don't know what exercise 7 refers to, hard to tell what steps you
have taken.
KB Article on certificates, including SelfCert.
http://support.microsoft.com/default.aspx?scid=kb;en-us;288985
After you get the certificate created you can check its properties. It will
be "untrusted".
To make it into a Trusted Certificate you must open the Microsoft Management
Console(Windows XP) by Start>Run "mmc"(no quotes).
File>Add/Remove Snap-in>Certificates.
Your new certificate will be under the Personal category.
Copy and paste it into the Trusted Certificates category. Ignore the alerts
and click Yes.
These selfcerts are machine-specific but can be used for multiple files.
Close out MMC and open Excel and your workbook.
Tools>Options>Security>Digital Signatures>Add. Add the signature.
Then you hit ALT + F11 to open the Visual Basic Editor.
Tools>Digital Signatures> follow steps to sign the project.
Save file and close it.
Next time you open you should get the pop-up screen allowing you to "always
trust" checkbox.
Works for me on Windows XP SP2(as well as SP1)
Gord Dibben Excel MVP