How can you tell if your computer is safe? Well that’s a trick question. You can never be certain that your computer is safe. You can check to see if your computer is safer then not, but the existence of the zero day vulnerability means that no one can be completely sure your computer is safe. Well I take the back. The only computer that is safe is the one that is locked in the basement, that doesn’t connect to any network ever, that only you yourself use. That’s about it. Other then that there are ways that you can check to see if it is safer then not. The first is look for any programs that show up that you don’t remember installing. Chances are if you didn’t install it and your younger brother or sister didn’t while you weren’t looking, then it’s someone malicious and your machine has been popped. Check to see if your machine is running slower then usual when connecting to network resources. If you find that when you connect to legitimate network resources, whatever they may be, that it’s much slower then normal then there is a good chance that there is some hidden process or program that is utilizing your bandwidth for nefarious means. If your machine is running much slower to open programs, save files, or any other type of activity that is disk i/o related and when you check your resource manager you see higher activity then what should be for just opening, closing, or saving a file then odds are your system resources are being utilized by someone that popped your machine. If you’re using your computer and you see the screen flash on you and you’re certain that it’s not a hardware failure, that could be indicative of someone remotely connecting to your machine without your knowing it. Some remote access programs cause the screen to do a quick blip when the remote attacker connects. If your friends tell you to quit sending them emails to refinance their mortgage, make a hundred thousand dollars quickly, or try to sell them certain health products then there is a good chance that your computer isn’t safe. It could be your email account was hacked, but the means by which it was hacked could have been a breach of your machine and stealing the credentials from there which would be easier then hacking Google, or worse yet someone could have setup an smtp relay on your machine and is using it to send out spam. Which brings me to my last observation, which is processes running on your machine that you don’t recognize. For example if you disabled smtp on your machine, but see it running and with high utilization, there again is a good chance your machine isn’t safe.