What it is
A trojan is malware that pretends to be something helpful (an app, document, or script) but does something harmful once you run it. Unlike a worm or classic “virus,” a trojan doesn’t spread by itself - it needs you to open or install it. Common trojan families steal passwords, spy on activity, or pull in more malware. Overview and examples: https://gridinsoft.com/trojan
Why it matters
One click can give criminals a foothold on your PC - leading to stolen logins, drained accounts, or even a later ransomware hit.
How it works
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Disguise: arrives as a “must-have” app, crack, driver, invoice, or update.
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Execute: you open it; the trojan runs and installs quietly.
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Payload: steals data, spies, changes settings, or downloads more malware.
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Persist: adds startup entries or tasks so it returns after reboot.
Red flags
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Prompts to disable antivirus or run as admin for a “viewer/codec.”
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Files from torrents or random sites that ask for unusual permissions.
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New tray icons, toolbars, or background network traffic you don’t recognize.
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Passwords suddenly stop working or you see logins from new locations.
Do it right
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Get software and updates only from official vendor sites or trusted stores.
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Don’t open unexpected attachments; scan downloads before running.
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Keep Windows, your browser, and security tools updated with real-time protection on.
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If you suspect a trojan: disconnect from the internet, run a full scan, change passwords from a clean device, and remove unknown startups; reimage if problems persist.