Microsoft OneCare

Onecare has now been on my pc for about half a day and has not detected any problems. It seems to be working ok although as I've just rebooted my pc this morning I got a message saying that there were some unexpected errors and that the report was not sent to Microsoft at the time but it would like to send the information now. The one thing I didn't like about the installation is that you have to uninstall any antivirus software you already have installed and you are also told to uninstall any firewall that is currently installed. Some people could take this literally and try to work out how to uninstall the XPsp2 firewall that is built in, although they are referring to personal firewalls such as zonealarm.
As the software installation is web based, I'm not impressed with the requirements that antivirus and firewalls need to be disabled beforehand as this could potentially lead to people getting infected whilst they install the software and are unprotected. It would make more sense to download the software onto the pc, disconnect it from the internet and then remove the firewall/av software, reboot and install. However with some pc's automatically connecting to the internet via modem I'm not sure how MS can guarantee that people don't reconnect on bootup (bearing in mind that this software is aimed at the non-pc literate user.)
I was also able to download the eicar.com test virus onto my pc before the antivirus component kicked in and complained that I was trying to download a virus. After I said yes to quarantine the file, I ended up with a file called eicar.com.{random characters here} in the directory. I repeated the experiment and I'm not sure why I've ended up with these files but curiously they are different sizes (and a lot bigger than the eicar.com source file). This has been logged with Microsoft because as far as I am concerned I should not be able to download the file onto my pc and I should also not be left with these weird files on the pc at the same time.
I've also noticed that thunderbird seems to be running a lot slower at the moment too but I'm not sure if this has anything to do with OneCare or not - it's likely to be the culprit but I'm not 100% sure at the moment. The online help file with the software is not very helpful - entering "Thunderbird" into the knowledge base came back with articles such as How do I find the correct disc for restoring my files, What do I do if I don't have a disc burner for Backup, What happens if I skip a disc while restoring files, How do I allow or block a program through the Firewall?, How do I upgrade or renew my Windows OneCare subscription?, Troubleshooting problems with updating Windows OneCare - most of which have nothing (or little) to do with thunderbird.
I've yet to try the backup routine although the annoying thing is that the window says that there are files waiting to be backed up but when you click on the backup now it then starts to scan for files to backup. This seems to be a bit pointless as surely the whole point of a background process is to have this information already. I can almost guarantee that there are always going to be files that need to be backed up as files are constantly changing on any pc that is used.