Two Norton Antivirus icons?

[Robai]

Sometimes there are two Norton Antivirus icons in Taskbar.

One of them is normal (it opens Norton Protection Center):

http://i37.tinypic.com/ejwy88.jpg

Other one looks empty, but it really is there (it opens Norton Antivirus):

http://i36.tinypic.com/155idzq.jpg

I think that this sometimes happens when I force to close (CTRL+ALT+DEL) some non-responding program (especially Internet Explorer, version 6.0), but I'm not sure.
(and please don't say me that IE v6.0 is not secure etc, because I'm tired of such comments and I already started to use Mozilla Firefox (v2.0.0.16), but I don't like it, because it is much slower)

If I restart computer then there is only one icon again.

Why? A bug?

System: WinXP+SP2, Norton AntiVirus 2007 (version 14.0.4.1)

 

[Robai]

Today I restarted computer and there is only one icon (as it often is):

http://i35.tinypic.com/nyidf7.jpg