If it is there after a reformat, did you restore your home directory
after reformatting? I would tend to agree with Wade that it would not
be a key logger. It is not impossible to get one, really, but it is
highly unlikely. However, this seems to be an Opera issue, so if
Opera is perhaps compromised and you can't get it off of the system,
don't use Opera until you have it figured out.

I would investigate where Opera keeps it settings in your home
directory and try wiping out that directory, since all your
application settings are stored in your home directory if you restored
it after a reformat, this would be why Opera didn't change. What
makes you think the icon is malware?