Google Chrome team posted in their blog with the report from Chrome users on support forum that Microsoft Security Essentials accidentally flagged Chrome as PWS.Win32/Zbot and on certain user systems Chrome was blocked and removed which later identified by Microsoft and apologized for the same and pushed updates to correct the problem. MSE did all wrong and corrected themselves, now here is what you need to do to get back or access Chrome in your Windows PC.
Restoring Chrome again after MSE incorrectly identified and removed Chrome as malware
How to check if my Chrome browser affected with MSE issue?
If you’re using MSE and Chrome browser is working perfectly then you don’t need to do anything.
What to do now to restore If I am affected?
Open MSE and update its definitions. Uninstall Chrome from add or Remove programs [Programs and features] and reinstall it again.
Google is releasing an update for this in next 24 hours which automatically repairs Chrome for affected users. If you can’t wait till the update, you can follow above manual method to restore Chrome in your system if you’re affected. [via]