Uninstall

I had the same master wordpass issue already described by lo_f and olivierdb.
I unistalled i-vault, and I found out a lot of left Comodo keys in the registery, among which the following two:
HKCR\Comodoivault\DefaultIcon and
HKCR\Comodoivault\Shell\Open
that cannot be deleted.

Can you tell me:
1- how to delete these keys?
2- Why all these left behind keys

Please help