Hi Leo!
Thanks for your reply! Unfortunately TASKKILL is a XP PRO only (I suffice with the Home Edition), so I googled for an alternative and learned two things:
First that I had that "Taskmanager Virus" which I had ignored up to then,
and second indeed found an alternative to TASKKILL:
[url=http://www.sysinternals.com/ntw2k/freeware/pskill.shtml]http://www.sysinternals.com/ntw2k/freeware/pskill.shtml[/url]
(I knew that site earlier and can recommend it!)
Merry Christmas :)