Don’t use your computer logged in as an administrator. Make your account a standard user (“Limited” user) and use that account for your daily operation. Only use administrative-level access when you are setting up your computer, installing new software or hardware, and the like. Then return to a limited account for your regular use.
If you get prompts about making changes to your computer, be especially careful. Clicking “Yes” may allow a malicious program to do something destructive to your system.