The first step in securing your computer (today we'll be talking about Windows) is to determine what's at risk. Learning as much as you can about your computer and network security will make it easier for you to assess when your system is at risk, and will greatly improve your chances of staying safe. 
Obviously, a computer that does not have access to the Internet, but is used as a typewriter, is much safer than a computer that is shared by several family members on the Internet. It may be used for downloading files or participating in online chat sessions, etc. Regardless of the intended use, there are three basic steps for your security: You should have anti-virus software (and keep it updated), never open files from sources you do not know, and always keep your system up to date.
Beyond that, there are a few other precautions that one can take that will further ensure the security of your computer.
1. Use a firewall. This will give you another layer of protection. You can have a hardware firewall - like the one on your router. There are also a bunch of 3rd-party software applications that you can implement in your operating system. Windows also has a Firewall.
2 Use as many “difficult” passwords as possible. Using your last name or your dog’s name as a password puts your security at risk. Much of this information can be easily discovered by hackers. Of course, you shouldn’t use your children’s names or other personal information. A strong password should contain letters, numbers, and special characters (like ?%*#@) that aren’t used to describe an actual word. You should also change your password frequently – at least every 30 days.
3. Rename the Administrator account. Because the Administrator account exists by default, it gives the hacker 50% of the information he needs to gain access to your computer. All he has to do is crack the password. To make things more difficult, a good practice is to rename the Administrator account.
4. Create a password for the Guest account. The Guest account is also installed by default and uses a blank password. Generally, the account is disabled and does not pose a threat. However, some hackers use utilities to enable the Guest account. With a blank password, it is very easy for them to compromise your system. Set a password for the Guest account, and leave the account disabled.
