Usually Windows does not automatically restart after installing updates but waits for you to click the restart system now button. I'd run the virus and adware checks and see what they bring up, if nothing it's most likely a conflict with the updates.

Try doing a system restore back as far as you feel comfortable then visit Microsoft Windows Update and do the updates manually. Also try uninstalling MSN Live Messenger before running the System Restore and seeing if it works after a clean reinstall?