I am getting very worry too and I am getting the same problem, and this is my first time catching a virus on HD which I never had a virus for 4 years straight. SHIT!.
When I run the Avast 4 Home and I do a full thorough scan with the archive file tick turn on scanning both drives C and D, no virus has been found.
Suddenly I went to Windows Explorer and do a manual quick scan high lighting the C drive, suddenly the quick scan had pickup a Blood virus the same problem as Technical.
Question how come the manual quick scan from Windows Explorer has pickup a virus, and the Avast 4 Home Anti-Virus software running a full thorough scan didn't pick it up.
Otherwise I am smelling a bug under my very own nose using the latest version, please advise.
I have set all my protection setting to High using Avast 4 Home, instend I don't have the Pro version for Script Blocking.