Microsoft Safety Scanner
Looks like Microsoft did sneak a new on demand anti-malware scanner past us. Most would have been unaware of the new application if not for keeping up with various IT newletters, blogs and web sites, such as I do on a daily basis. This small application is downloaded as an .exe file and instead of being installed onto your Windows enironment, it is just ran directly from the .exe file to start the scanning process. One of the downsides to the program is that you have to re-download the file again, after ten days, to include the latest definitions for the program. If your willing to live with the small inconvienence, it looks like a good additional on-demand malware scanner, in additional to you main persistant anti-malware program. Just don't depend on this one alone as your main anti-malware program for your Windows OS environment.