Identify if the computer has started getting slow all of a sudden. All Windows operating systems tends to get slow with the passage of time, however, if there is rapid degradation of performance, it indicates the presence of malware.
Look out for any unwanted toolbars or plug-ins installed in your browser without your consent. Click on start on the lower left corner of the screen, and select ‘Control Panel’ from the second tier of the popup menu. Click on 'Add and Remove Programs' to see the list of installed softwares on your computer system.
If you have installed new software in the near past, check out for any additional softwares packages that might have been installed along with it.
Internet speed gets also slow when the system is infected with malware. Check out your home page settings, and if they are changed, it indicates the presence of some sort of spyware. Also check out for any popups that gets loaded even when you are disconnected from the internet.
Computer freezes up or gets stuck when it is overloaded with malware. The booting and shutting down of the system also increases manifold. If the applications that used to open up in a few moments are taking an extended amount of time, the most probable cause is virus or worm.
Open your task manager and observe the amount of memory consumed by the programs. When computer gets infected with malware, RAM usage increases by manifold. Moreover, the computer becomes extremely slow and the applications that used to open up in a few moments take ages to load.
If your computer has any of the above mentioned symptoms, it’s time to get your it completely scanned by Antivirus software.