It's very easy to secure your computer against hackers, viruses, ransomware, spyware, and spam, and it's mostly free! Just follow the guidelines on this page...
Install a Firewall
This stops people connecting to your computer over your Internet connection. More importantly, it stops any programs installed on your computer connecting to the Internet unless you give it permission. Windows has a built-in firewall, but it only stops incoming connections.
Install Anti-Virus software
This stops viruses getting onto your computer, and also stops you accidentally sending viruses to other people. Once installed, keep the software up-to-date with the latest virus definitions or it can quickly become useless.
Keep your Windows operating system bug free and up-to-date to stop new viruses or worms getting into your computer.
For your Windows login password and all other passwords, e.g. your email password, choose a password that contains letters, numbers, and at least one punctuation character. For example, mic_1567.
When surfing the Internet, or installing some free software, your computer may get infected with Spyware. Spyware is not a virus, but instead it reports on your surfing habits. This helps marketing companies target you with their junk email (spam).
The majority of viruses are transmitted via email as attachments. So, never, ever, ever open any email attachments, or click on any links in the email, unless you know the person and know that they are sending you the file. Remember that you will receive viruses from people you know because the virus will use your address book. So just because an email comes from someone you know does not mean that it is virus free.
You will lose important files on your computer, either by accident or hardware failure. The only way to avoid such a disaster is to backup your important files regularly. You can backup your files using this sites free SyncBackFree program. Remember to store the backup on another computer, in the cloud, or on removable media.
A number of web sites use pop-ups, those annoying small windows of adverts. Although they are safe, they are annoying. Many browsers have built-in pop-up stoppers.
Although generally not a security issue, spam (unsolicited junk email) can be extremely annoying. You can avoid receiving spam by making sure your email address is not public knowledge. For example, if you post to newsgroups then use a mangled email address, e.g. Admin@nospam.mjleaver.com. In your signature tell people to remove the nospam. part of your email address before replying. If you are already receiving spam then use a spam filter. Never reply to spam. Just delete it. See spam don't buy it for more information on stopping spam.
Keep your software up-to-date. For example, make sure you keep your anti-virus and spyware removal software definitions current so that they can stop new viruses and spyware.
The vast majority of viruses take advantage of the fact that most people use Windows and Microsoft software. If you use a different web browser, e.g. Mozilla Firefox, a different email program, and different office software, e.g. the free OpenOffice package, then your chances of getting a virus are reduced (and you save money).
You should only install software from sources you trust, i.e. purchased software. Don't install something downloaded from a P2P network or something someone sent you via email.