I have experienced exactly the same set of circumstances this morning. A greater problem is that I am now locked out of my server and all other computers on my office network.
I did using Windows to remove One Care, then re-installed it to no avail. I then tried to use the NT function in XP Pro to revert back to earlier settings (yesterday), and it still acted like it was trying to load a new version of One Care Live.
No matter what I have tried, without checking the URL's in the thread, I can not open One Care Live when I click on the icon.