Hello.A well protected computer should have at least an antivirus and firewall, an antispyware is also great addition to your computers security.
1. Install an antivirus. Good and free antivirus programs: Avira
2. Install Spybot - Search and Destroy
This will provide real-time spyware & hijacker protection on your computer alongside your virus protection. You should also scan your computer with program on a regular basis just as you would an anti virus software.
3. You should use a firewall. Without a firewall your computer is susceptible to being hacked and taken over. Simply using a Firewall in its default configuration can lower your risk greatly. I would recomend, only install one of these: PC Tools Firewall
(only Install the Firewall as a standalone if you already have an AntiVirus installed on your computer).
After you install the third party firewall, please disable your Windows firewall. Please go to My Computer >> Control Panel >> Windows Firewall
and choose Off (not recommended) option. Then please click Apply and Ok.Additional utilities that will enhance your safety.
1. Install SpywareBlaster
This will added a large list of programs and sites into your Internet Explorer settings that will protect you from running and downloading known malicious programs.
2. MVPS Hosts file
The MVPS Hosts file replaces your current HOSTS file with one containing well know ad sites etc. Basically, this prevents your computer from connecting to those sites by redirecting them to 127.0.0.1 which is your local computer.
3. Download and install the free version of Winpatrol
4. Use an alternative Internet Browser. Many of the exploits are directed to users of Internet Explorer. Try using a different browser: Firefox, Opera.