It looks like Microsoft is no longer providing support for the original version on Windows Vista. In order to get support going forward, you need to upgrade to Windows Vista Service Pack 1 or Windows Vista Service Pack 2.
You can read more about the end of support for Windows Vista RTM here.
If you haven’t yet upgraded to SP1 or SP2, hopefully this is motivation for you to do so. If you’re concerned about upgrading, both service packs have been out for some time and I cannot think of any reason not to upgrade, to at least SP1.
The upgrade process is simple and straightforward. Visit the Microsoft Download Center to get a copy of Windows Vista Service Pack 1.