Acronis Antimalware CD is an image of a bootable CD which is able to scan your PC to detect and remove malware.
This may be useful if you have an infected PC which will no longer start, for instance. Or if you suspect your PC has contracted something nasty, but your regular antivirus tool hasn't raised any alerts, then the Antimalware CD may give you a better chance of finding and removing the threat. (By booting from the CD, not your own perhaps compromised Windows installation, you should bypass many of the mechanisms which stealthy malware uses to protect itself.)
The Antimalware CD works much like most similar tools. Burn its ISO file to a CD, boot from it, and the program will load. If there's an internet connection available then the tool will update its signatures, and you can then begin a scan of all your hard drive partitions with a click.
And as a bonus, the CD also includes a copy of TestDisk, an essential free tool which can detect and fix partition-related problems that might prevent your PC from booting normally. So if your PC won't start and the antivirus scan reveals nothing, try that instead (it's the File Recovery shortcut on the desktop), but be careful - poorly judged partition tweaks can cause more problems than they solve.
Please note, the Antimalware CD is just one part of Acronis' Backup and Security, which combines a powerful internet security suite with disk imaging and online backup tools. Acronis have made the CD available to everyone, for free, but unsurprisingly are only offering technical support to those who have purchased the full Backup and Security package.