If you're seeing some of these problems with Chrome, you might have unwanted software or malware installed on your computer:
Pop-up ads and new tabs that won't go away
Your Chrome homepage or search engine keeps changing without your permission
Unwanted Chrome extensions or toolbars keep coming back
Your browsing is hijacked, and redirects to unfamiliar pages or ads
Alerts about a virus or an infected device
In the future, avoid unwanted software by only downloading files or visiting sites that you know are secure.
Computer Android
Before you reset your browser settings on a Windows or Mac, check your computer for unwanted programs.
Check your computer for malware (Windows)
Chrome can help you find suspicious or unwanted programs on your computer. If Chrome finds an unwanted program, click Remove. Chrome will remove the software, change some settings to default, and turn off extensions.
You can also check for malware manually.
Open Chrome.
At the top right, click More Settings.
At the bottom, click Advanced.
Under “Reset and clean up,” click Clean up computer.
Click Find.
If you're asked to remove unwanted software, click Remove. You may be asked to reboot your computer.
Manually remove malicious programs (Mac)
You can remove malware and other programs on your computer that you don't remember installing.
Open Finder.
On the left, click Applications.
Look for any programs you don't recognize.
Right-click the name of any unwanted programs.
Click Move to Trash.
When you're done, at the bottom, right-click Trash.
Click Empty Trash.
Restore quarantined files (Windows)
Chrome can help you find suspicious or unwanted programs on your computer. If Chrome finds an unwanted program, Chrome will remove the software, change some settings to default, and turn off extensions.
If you think Chrome removed a file that’s safe or personal by mistake, you can restore the file.
On your computer, open the folder %USERPROFILE%\AppData\Local\Google\Chrome Cleanup Tool\Quarantine.
Open the folder Quarantine.
Click Continue.
Right-click the file you want to restore and click Extract all.
Enter the password chrome_cleanup.
To learn more about what data is collected and how it's used, read the Google Chrome Privacy Whitepaper.
On your computer, open Chrome.
At the top right, click More Settings.
At the bottom, click Advanced.
Chromebook, Linux, and Mac: Under "Reset Settings," click Restore settings to their original defaults Reset Settings.
Windows: Under "Reset and cleanup,” click Reset Settings Reset Settings.
If you removed unwanted programs or reset your browser settings, you might need to turn some extensions back on. To turn extensions on, at the top right, click More More Tools Extensions. Only turn on extensions you trust.
Still not working? If the steps above don't work, visit the Chrome Help Forum.
How to spot malware (video, 2:30)
Three tips for spotting malware (2:30)
Learn what to look for when you have malware on your computer and how to stay safe online.
How to avoid malware in the future
Watch out for things that look too good to be true. Winning a contest or getting expensive copyrighted content for free is sometimes a trick to get you to download malware.
If you haven't recently run a virus scanner, be wary of warnings about viruses or infected devices. The site might be trying to scare you into downloading unwanted software.
Only download files or visit sites that you know are secure. Learn more about healthy browsing.
If a popup about updating or downloading a program looks suspicious, don't click on it. Instead, go to the program's official website to download it.
Source:- https://support.google.com/chrome/answer/2765944?hl=en&ref_topic=7438008