MSN Messenger 6 Installed but Windows Messenger 4.7 dialog..

Hi all,

(Damn! Messenger must be one of Microsoft's most useful and at the same time
exceptionally irritating apps ever...)

After successfully closing ver 4.7 (yes, it was NAV - thankyou JK), I
installed ver 6.0 thinking my problems were over...
But to my surprise, the first time a contact came on-line the 4.7 alert
appeared, and when she sent me a msg the 4.7 conversation box opened.
After checking through my program files I see that both programs are still
installed and have been completely unable to remove 4.7 (even from the
command prompt).
I have the intuition that ver 6 still NEEDS a previous version's components
but, as usual, MS's un-transparent installation process certainly doesn't
make this clear.

Various questions (sorry...):

1. Is it the case that both progs must be installed? (and if you have a
moment - why, for crying out loud!?)

2. If the answer to 1. is "no" - then how do I get rid of 4.7? If it's
"yes" - what should I do to make 4.7 "disappear" for everything except
whatever background processes it needs to be there for? (which are what
precisely?) Having installed ver 6, I certainly don't want ver 4.7
conversation boxes popping up...

3. I can see no reason for starting Messenger automatically on logging in to
windows (using up valuable recources) but would like to do so on connecting
to the internet - is this possible? (I mean without a homemade .bat
file...).

4. As JK pointed out, NAV's Messenger scanning option seems to cause
problems - luckily Messenger 6 has a virus scan option. I would like to
point it to NAV but am unsure to which file precisely I should be directing
it to automate the scan (I have Norton Systemworks on WinXP and my desktop
shortcut targets "common files\symantec shared files\Nmain.exe" while my
start menu NAV shortcut targets "Norton systemworks\Norton
Antivirus\Navui.nsi" - but both open Systemworks...) can anyone help?

and finally 5. I don't suppose there is any way of "cleaning up" the ver 6
window? I mean of getting rid of all the MSN plugs in the left-most column
(horoscopes and lonelyhearts no less...) and the eye-catchingly and
irritatingly constantly changing MSN ads at the bottom...?

Thanks in advance for the help,
B.