Windows XP. I have been using Virgin Media PC Guard anti virus for a number of years. Recently the programme will not load at startup as usual and requests a startup. I have discovered an avprog in c:/ Program Files/Common Files called Authentium which appears to be the problem. This programme does not appear in the list of programmes in the Control Panel so I cannot remove it. My Windows Explorer 7 tool bar has no Print option and is different in layout to my wife's computer. I have deleted all the files from Authentium as listed since there is no delete option for the programme, but they reappear when I next switch on. Help!!!