This is kind of ridiculous (1.2 install problems) (yes I read the stickies)

[Ars Moriendi]

Going straight from 1.0 to 1.2 is the recommended way to go, or so the popular opinion says. That's how I did it and it went smoothly with no problems...

Try the following :
1. Uninstall M2TW
2. Backup your save, mod, tga and replay folders
3. Delete the SEGA folder from Program Files
4. Run regedit, search for HKEY_LOCAL_MACHINE/Software/SEGA key and delete it
5. Uninstall .NET (Control Panel > Add / Remove programs)
6. Reboot
7. Re-download the patch from a different source ; make sure it's not the leaked version
8. Install 1.0, then 1.2 (don't run the game before 1.2 ; don't run the unpacker after)
9. Start the game ; pray...

EDIT : the M2TW uninstaller might offer to remove all folders ; I don't remember if this is the case. It might also remove the registry keys - but you need to check and make sure it's all gone. CAUTION : If you have other SEGA games installed, you need to be more selective when deleting folders and registry key - only remove those pertaining to M2TW, not the whole SEGA folder/key.

About your logon problem, try this and see if it works :

1. start > run > type "control userpasswords2" in the "open" box.
2. the user accounts settings should pop up
3. uncheck the "Users must enter a username to use this computer" option
4. Reboot

I can't help much with the firewall. Only one suggestion - if you're on DSL, many modems have an integrated hardware firewall which is disabled by default - check your modem manual and the setting application for clues. If you have it and succeed in enabling it, it should work better than software firewalls, as it doesn't use resources on your PC to do its job. Warning : don't take my word for it as I'm not exactly an expert - do some research or ask somebody who knows.