You're using MSN software which is separate from Windows. I use the MSN
service but don't use their software so can't help with those questions.
There may be a section in there for "accounts" where you can change the
user that the software defaults to. If not, you'll need to check the MSN
help pages or give MSN another call.

There are two Messenger programs - Windows Messenger which comes with
Windows XP; MSN Messenger which is installed separately. You may have one
or both installed on this laptop. Both can have their automatic startup
"turned off."  To do this:

Open the Messenger program. Look for the Preferences menu. It's usually
under Tools> Options. Under "General," uncheck the box next to "Run when
Windows starts."

If using Outlook or Outlook Express, look for similar settings in Tools>
Options that relate to allowing Messenger to run whenever the mail program
is launched.  Also in Outlook Express, go to Views > Layout and remove the
check box from Contacts. This helps stop Messenger from reappearing.

1) I don't know where you have an email name showing up that you don't
want. I suspect it may be under your user account and that is the .NET
passport currently associated with it. If this is the case, you can go to
Control Panel> User Accounts and click on the relevant account name. Then
use the 'change my .NET passport" to change to the passport address that
you prefer.

2) Contacts in CC mails: That's how CC works. Use BCC to stop other names
from being displayed.

There is also an autocomplete setting in Outlook and OE that can be turned
off (list of names appearing as you are typing in an address). Look in
Tools> Options for the setting.

3) hard to answer without knowing what email program is in use.

In general, any user should be able to use the browser to sign in on the
web interface for their email accounts. This doesn't take any extra
configuration steps on your part and won't mess up your settings in the
email program that you're using.
 
If on the other hand, you are referring to other MSN users that want to use
your software to sign into to their accounts - I believe you have to log
off of the service and then they log on with their account. Check with MSN
to be sure.

4) What? Describe this problem in more detail. Can't tell from this
description if you have a setting problem with text colors or if windows
need to be resized.  What program are you viewing in?