All computers connected to the Internet are at risk for malicious (viruses, spy-ware, ad-ware, and various unrequested security intrusions) attacks. These attacks can result in loss of data, change of data, prohibit access to your data, hardware failures, and disruption of destruction of applications and operating system and business processes.
One of the first steps one should take is to make sure a system has a current version of anti virus and anti spy ware software installed. Additionally, definition files (list malicious software signatures) should be current. After installing protective software, immediately update both the software and signature files. Often, one will be prompted to do update.
Additionally, do not open suspicious mail or venture to questionable Web sites. By visiting a malicious Web page, your system can become infected. When in doubt, do not try to access anything you find suspect.
Keep all of your Web browser, application, and operating system files up-to-date. Windows allows systems to automatically check for updates. This is a good option if you do not want to manually check for updates. However, the automatic updates function does not always work and will not work if infected by malicious software that disables automatic updates.
Some warning signs that indicate the possibility your system is infected are that your system runs slower than usual, you are not able to access the Internet using your Web browser, you continually find that your Web browser is redirected to an unrequested Web site (a common redirect is to Google), unusual or unexpected pop-ups appear, you are not able to start your system or shut it down, or various software errors appear.
Become aware that some Web sites advertise to scan your computer for viruses or spy-ware. Be careful of these advertisements because some sites install applications on your system without your knowledge. Some vendors will provide a link to uninstall their programs and for those who do not, consult Internet resources or take your system to a professional for resolution.