Warning: Never download any Anti-virus or Anti-Malware or any kind of security solution which comes in the form of Ads on Internet on different websites or by random email addresses. These are malwares controlled by malicious hacker groups.

Make sure your PC's Firewall is turned on (Always), Windows Operating Systems come with built-in firewall solutions, never disable your firewall. When you disable your firewall, your PC is vulnerable to Internet attacks.

I recommend you use free Anti-virus solution by Avast, which can be found at Avast.com (Home Edition) or download MSE (Microsoft Security Essentials) from Microsoft.com (which is also free for Genuine Windows users).

Note: If you're running only Anti-Virus software in your windows, download Windows Defender from Microsoft.com and install it. Windows Defender is Anti-Malware solution free by Microsoft, but if you're using MSE, then you don't need Windows Defender. Alone anti-virus is not effective for your computer's protection.

What do Firewalls do? I've never understood this... it doesn't block any internet-using programs, it seems (or maybe I have it off at all the wrong times), but instead just seems to sit there :/ Then again, my Firewall is always down for the sake of online gaming, and anyone who I've played any games LAN-ly with do the same, so I've never been told reason to keep it up - only down :/ (my life is plagued with bias)

And, thanks for the suggestion of what Anti-virus program to use... I've been looking for a new one for a little while..... The only thing SuperAnti-Spyware has ever picked up was a program I made to try making a file a non-system file, and K7 picked up everything as a virus >.> So I'll need try that (yes, I am careless, not only with internet security, but with everything else involving computers as well... how many times have I dropped hard-drives, broken floppy disk-drives, accidentally spilled stuff on the keyboard...)