On Windows XP SP3 Security centre, I get the message ‘Windows found more than one antivirus on this computer.’
Comodo Internet security is the only program installed.
Do I need to check in the registry there are not traces of previous antivirus programs? I did have Avast and AVG installed at different times a while ago but they were properly uninstalled.
Sounds like a corrupt Wbem repository to try to repair, try the following line in your command prompt then press enter. rundll32 Wbemupgd, Upgraderepository
If that fails try the next lines in command prompt followed by enter after each line to rebuild repository. net stop winmgmt
rd %systemroot%\system32\wbem\Repository
net start winmgmt
Edit: You may copy/paste each command line in preference to typing them if desired.