We have had an instance where a client was unable to access Vizulate from Windows Vista.
It appeared that after pressing "new chart" - the "loading vizulate" in the bottom left corner of excel work display and nothing would appear to happen.
This issue was caused by Vizulate being unable to access the license server in order to verify that there is a valid installation of Vizulate.
You can confirm this cause by navigating to https://serialkeymanager.com If there is a (trust) certificate error on this page then it is likely that this is the underlying cause. I.e. If Internet Explorer warns you that this page is not trusted.
To resolve this issue, you will need to explicitly trust the serial manager website. To do this - add a trusted certificate authority for the organisation which issues the serial key manager certificate (a little complex I know!)
Create the "Thawte Code Signing Secondary Intermediate CA Certificate" certificate within notepad as a .cer file and then install this certificate.
After doing this - close Internet Explorer and try again to access the serial key manager webpage. There should be no certificate errors. If this works correctly, close Microsoft Excel and reopen it. Activating Vizulate should now pass the license check and should open giving you all of the features of Vizulate.