avast! 4 Professional antivirus, anti-spyware & anti-rootkit for Windows. The professional solution to great protection avast! 4 Professional Edition represents the best antivirus protection available and can be downloaded and used free of charge for a 60-day trial period. At the end of the trial period, a license key must be purchased. avast! 4 Professional Edition comes with anti-spyware, anti-rootkit and strong self-protection built-in. All-inclusive, comprehensive protection avast! 4 Professional Edition includes ANTI-SPYWARE protection, certified by the West Coast Labs Checkmark process, to protect against the latest spyware threats and ANTI-ROOTKIT DETECTION based on the best-in class GMER technology, built in to the scan engine. Main New Features Anti-spyware built-in Anti-rootkit built-in Strong Self-protection No additional purchase is required. 60 day trial for Windows 95 to Vista.