We use Kaspersky Ant-Virus as our standard on all of our networks and sell quite a bit of product. These are typically license packs installed with the administrator pack. We also have workstations brought into our repair center with virus software installed, but are contaminated with viruses that were not caught, mostly because of expired licenses, but often also that the installed ant-virus software did not do its job.
Sometimes these viruses make the workstation unusable. Anti Virus 2008 and Anti-Virus 2009 are good examples of this. Downloading and installing Kaspersky or running any sort of web based scan becomes impossible as you cannot keep the browser window open long enough to install anything.
It would be very useful to have a bootable CD that would save the updated definitions to a thumb drive. This way you could insert the CD, plug in the thumb drive, boot, update the definitions to the thumb drive, and run a scan. Once the computer was clean and usable again, you could then download and install Kaspersky.
Not only would this make a great technical tool, it would also make a great sales tool. Once the computer was clean it is easy to tell the customer "OK, Kaspersky cleaned it off, now to stop this happening again we need to replace your existing anti-virus software, because it clearly failed, with Kaspersky as it found the viruses your existing software did not." Easy sale.