Next time it starts up right-click the tray icon or find the options menu in the open window and tell it not to log in automatically.
I know I've disabled MSNIM from starting in several different systems, but it will always load when you open Outlook and close when Outlook closes (yeah, so don't use Outlook). Sorry I don't remember the exact steps to turn it off, but it's there.
When 5.0 loads (as it hopefully will now) you can set it up the way you want it (per MS approval).
If all else fails you can try to reinstall 4.7, then uninstall it, then install 5.0 again - that's a typical procedure in Windoz.
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| Ric