Mail vanished? Onecare installed?

This may be the reason email has been vanishing from my parents in law computer. A couple of times they have had emails disappear from outlook express, normally after a maintenance period has occured on the pc. Although they have Onecare “installed” it’s not working properly as Microsoft still can’t fix the bug where onecare can’t talk to the activation server to let it know it has been installed on the pc. Some parts of onecare work, like the firewall and the ability to delete mail at random, but the virus updates don’t (and you get an annoying red box popup each time you reboot the computer)