In 10 tips only, you can increase the security of your PC:

1. Physical Security: 

Put your PC in a safe place with a door lock.

2. OS installation strategy: 

When you install the OS, make two drives at least, put the OS on a drive and your files on other drives. In some cases you might need to reinstall the infected/damaged OS on its drive without affecting your files in other drives.

3. Antivirus:

Install an antivirus and keep it updated. The best time to install an antivirus is after OS installation immediately and even before installing device drivers.

4. USB Disk Security:

Antiviruses are weak against USB flash memory viruses because these kinds of viruses can run by just double-clicking the flash memory drive using some “auto-run” malicious files. These viruses can turn off your antivirus and can prevent you from browsing antivirus websites. Therefore, practically, use USB Disk Security or similar program to catch malicious files and delete them once you plugged in a USB flash memory.

5. OS Service Packs:

Install the latest Operating System (OS) or keep the current OS updated with the latest service packs and security updates.

6. OS Firewall:

Turn on OS firewall to close all non-standard and non-required ports in the PC. Then you can open certain ports for certain software.

7. OS Account Password:

Create a password for your PC.

8. Lock the screen:

Get used to lock the screen whenever you have to leave the PC. You can lock the screen by pressing (windows key) + (L) together.

9. Toolbar, adware and others:

Keep alerted not to install unknown software on your PC. Only install trusted and famous software from trusted websites. Otherwise, you will suffer very much from unusual behavior of your PC.

10. Backup your files:

Your files are more important than any PC. All what we have done above is for the favor of your files. Therefore, make recent copies from your files to external hard disks, DVDs or to a “drop box” account. You will not know when your PC will be stolen, damaged, becomes infected by strong viruses or at least will suffer from hard disk extreme failures or any similar things (cloud your files).