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Malware help

You can find answers to common questions about malware and virus infections on this page.

If you can't find the answer you're looking for, see these other topics:


You can also visit the Microsoft virus and malware community for more help.

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Win32/Keygen is the name we give to programs that claim or try to illegally activate software.

Of the two million PCs every month that are detected as having Win32/Keygen, nearly 50 percent are also infected with malware. Some of the most dangerous malware pretends to be a keygen, such as Win32/Sirefef.

Go to our software piracy information and piracy prevention pages for more information.

Most malware tries to stay hidden, so you may not be able to tell.

Some of the more common symptoms include:

  • Your PC takes a long time to start up.

  • It takes a while to start an app or change between apps.

  • You get a lot of "delivery failed" messages that say you tried to send an email.

  • You notice unusual icons on your desktop or in the notification area on the taskbar.

  • Your web browser doesn’t go to the site you tell it to, has a different start page, opens new windows, or has new toolbars and shortcuts.

  • You get lots of error messages popping up.

Go to our malware infection page to see the most common ways malware can infect your PC.

There is no way to guarantee your PC will be safe from malware. However, there are several ways you can reduce the risk.

The following web pages have some simple tips to help you stay safe:

These articles can help you stay safe from common threats:

Go to our software updates page for links to update vulnerable software.

Malware authors can use known vulnerabilities in common software to attack your PC. Software vendors regularly release updates to fix these vulnerabilities. The best way to stay protected is to keep all your software up-to-date.

Go to our exploits page for more information about vulnerabilities and exploits.

You can find answers to common issues and questions at the Microsoft Community Virus and Malware website.

If you think your PC is infected you can also go to these sites:

If you suspect a file includes malware or potentially unwanted software you can submit it to us for analysis.

Go to our encyclopedia for descriptions about specific threats.