system
5
These are all hallmarks of spyware, malware, and/or trojans, not respected antivirus companies.
Or an error somewhere in the program.
I have win 7 64, and tested the method I posted before posting, and it was gone, so there may well be something wrong with the installation.
Also, I believe that the persistance of the gadget was an issue with a previous version - i.e. a bug, so what version of avast are you using?