If you don't know the password of your Trend Micro OfficeScan client, you can still do the uninstallation by changing a value in the registry.
You should be able to uninstall the client without a password prompt.
Although unsupported, it is possible to install Microsoft Security Essentials on a Windows Server 2012.
To do this, set the compatibility of the downloaded file to Windows 7, then start that file with the parameter /disableoslimit.
The installation goes without a problem, and as far as I can tell, there are no compatibility issues.
A note of warning I read on the Avast Forums: if your Avast subscription runs out, the Exchange Information Store no longer starts and bails out with an error "failed to start virus scan". Very annoying indeed...
A new type of rootkit has recently been seen. While most modern rootkits use the MBR and unused sectors of a harddrive, this one also misuses NTFS metadata to inject malicious code into a running OS.
In case of an infection with phony anti-spyware software (such as Anti Spyware 2009), where the EXE file association has been corrupted, use these Registry fixes to reset them to default behaviour.
Currently, the official Avast for Mac Edition available for download is still at version 2.74, released somewhere in 2007.
This version still has many annoyances and bugs that have not yet been resolved (one of these issues is the ability to run automatically in the background, without the main window popping up at start up each time).
Luckily, the Avast Forum has a post, providing a new release candidate is available for download for some time now. The build is also a bit outdated but has at least many fixes that aren't present in the official release.
The direct download link is: http://public.avast.com/~cimbal/avast.3.11.zip.