Generally the symptoms are visible or they do leave a hint,
Does it take longer than normal for your operating system to boot up?
Are you waiting too long for some of your programs to start?
It is a known fact that malware has the tendency to slow down your system, your Internet speed or the speed of your applications.If you notice something like this and you’re not using any heavy program or application.It might indicate a malware attack
One of the most annoying signs of malware is the unwanted pop-up windows. Unexpected pop-ups which appear on the system are a typical sign of a spyware / malware infection.The main issue is created not only by the numerous pop-up windows that affect your Internet navigation, but also because it is quite difficult to remove them from the system.
Pop-ups are not only annoying, but they usually come bundled with other concealed malware threats and which could be far more destructive for our systems.
To avoid such spyware and their impact on your system, keep in mind a few security practices:
To remove this type of threat, you need a very good security product against spyware. A few popular products capable of removing spyware from your system are Malwarebytes, Spybot Search and Destroy, and such applications.
If your programs or your system crash constantly or you see the infamous BSOD (Blue Screen of Death) regularly, it’s a clear warning that your system is not working properly and you should look into it.
There are two things that can cause this type of issues:
Simply run a complete scan on the system with a good antivirus product. You should have a reliable security solution on your system, which should include real-time scanning, automatic update and a firewall.
To find the best solution, check the antivirus test results run by big company names in the security industry, such as AV Comparatives, PC Magazine, AV-TEST or Virus Bulletin etc
If you notice excessive activity even when you don’t use your computer and there is no program or download running at that moment, this could be the right time to check your system for malware.
Another sign of malware activity, since there are numerous types of malicious software which use various methods to fill up all the available space in the hard drive and cause it to crash.
There are cases where the user is not connected to the Internet through his browser, and there is no program that may connect to online servers to download or upload any data, but high network activity can still be observed.
First of all, we need to check the following:
If the answer to all these questions is No, then maybe you should check where all that traffic is going.
Have you noticed that your home page has been changed and you don’t remember doing it yourself?
Did a new toolbar pop out of nowhere and landed at top of your web browser?
Have you tried to access your favorite blog, but you were redirected to a different address?
Run a complete scan with your security solution as soon as possible. Because these type of threats don’t go away easily. Make sure you run additional scans with specialized software, such as anti-spyware programs as the ones mentioned above.
Though the root cause may be a technical one, it could also be a sign that malware has compromised your system. If this is the case and you lost access to some important areas of your operating system, you need to prepare for the worst. These are the cases when a complete wipe and reinstall of the operating system is taken into consideration.
Are your friends tell you that they received suspicious emails from you or instant messages from your social media account, which often include attachments or links?
I have shared a very comprehensive Facebook Spam techniques on my Forum (http://archive.drhack.net/tabid/27/g/posts/m/5750/Facebook-Spamming--Jungle-Fire.aspx) which will guide you how such things work
If you discover the messages were sent from one of your accounts, take these steps: