Prevx is a computer application designed for the removal of and protection from malware

Malware

Malware, short for malicious software, consists of programming that is designed to disrupt or deny operation, gather information that leads to loss of privacy or exploitation, or gain unauthorized access to system resources, or that otherwise exhibits abusive behavior...

. There are separate real-time and on-demand versions. The software downloads in a few seconds because it is 800 kilobytes. The software can remove low-risk adware

Adware

Adware, or advertising-supported software, is any software package which automatically plays, displays, or downloads advertisements to a computer. These advertisements can be in the form of a pop-up. They may also be in the user interface of the software or on a screen presented to the user during...

 for free, but the user has to purchase and enter a license key if it is more serious. Scanning can take anywhere from less than two minutes to five minutes.

Reception

Tony Bradley, of About.com

About.com

About.com is an online source for original information and advice. It is written in English, and is aimed primarily at North Americans. It is owned by The New York Times Company....

, liked the software except that he had some confusion about configuring the interface and that key protection is disabled by default although the issue referenced has since been corrected.

Controversy

Prevx stirred up controversy amongst the internet communities when they announced on November 27, 2009 that a recent Windows update was causing a "Black Screen of Death", affecting users of Windows XP, Vista and 7. They claimed this bug rendered the machine unusable. It was later discovered that the black screen was caused by a malware infection, unrelated to the Windows update. Prevx has been criticized for their strong accusation towards Microsoft and for not backing up their claims with any kind of technical data.

Acquisition

In November of 2010 Prevx was acquired by US based Internet security company Webroot. The full conditions of the deal were not released but the announcement was made that Webroot will fully integrate Prevx's behavior-based antivirus technology into their existing software and also make Mel Morris, founder and chief executive of Prevx, the vice president of Webroot's Prevx division.