Moved from SaaS Total Protection Service to SecurityCenter (home products) as I think that's what you sre using, correct me if I'm wrong.
When uninstalling Kaspersky did you run their removal tool?
Run that then:
Uninstall McAfee via Control Panel > Programs
Then run the MCPR cleanup tool and reboot.
Reinstall McAfee from your online account.
Also ensure that your Vista is totally up to date, i.e. Vista SP2 (anything less please post that information as I may be able to help) and you should also have, even if you don't use it, IE9 installed.