Suspicious Programs Appearing
A program, icon, browser toolbar or background process appears on the computer that you don't remember installing yourself.
Quick answer: Programs you don't remember installing are usually bundled software that came attached to something else you did install, rather than a deliberate attack — but that doesn't make them harmless, and some are genuinely malicious. Check what it is before assuming either way.
Likely causes
- Bundled software attached to a free program installer, often opted into by default during a quick installation
- A program installed by someone else with access to the computer
- In less common but more serious cases, malware that installed itself without any visible prompt
What you can safely check yourself
- Check when it was installed (Settings > Apps, sort by install date) and compare that to what you remember installing around that time
- Search the exact program name online before removing it, since some system-related programs look unfamiliar but are legitimate
- Remove anything confirmed as unwanted through Settings > Apps rather than just deleting a shortcut
When it needs a proper look
If you can't confidently identify what a program is or whether it's safe to remove, or several unfamiliar programs appeared around the same time, a proper scan is worth doing before removing anything yourself.