plugging in my USB drive, but got a virus...

Hi Paul

Malware on a USB flash drive is generally caused by a Trojan infection on a PC that the USB flash drive has been connected to . ..

The trojan will install Autorun and a couple of other files onto the flash drive, it is a way of self-replicating on more PC's

You need to run a full scan on any PC that USB flash drive has been connected to, in order to find the original source of this infection, then remove that infection from that originating PC and also any USB flash drives that have been connected to that, otherwise, the next time you connect an infected USB flash drive the PC will be infected again . . .

Hi Paul

If that is the only device, that USB flash drive was connected to, then yes, you need to scan that PC . ..

If that USB flash drive was used in another PC and Defender blocked the Autorun on your PC, then your PC is not infected, because that did not get a chance to execute and infect your PC!

Malwarebyes is the most powerful malware scanner but slightly different than an anti-virus like Defender. I would keep Defender for best performance, but periodically or if in doubt run Malwarebytes.

As I wrote above it is free, and how to disable it's Real Time Protection trial version in Account Settings.

After installing, in the Scan settings choose to include the flash stick and also to Scan for Rootkits.

Hi Paul

Once those PC's have been scanned and nothing has shown, that should never appear again . . .

Hi Paul. I'm Greg, an installation specialist and 9 year Windows MVP here to help you.

Run a full scan with the most powerful on-demand free scanner Malwarebytes:

https://www.malwarebytes.com/mwb-download/. In the Scan Settings first set it to include scanning for Rootkits.

Clean up anything found, restart PC and then run again until it comes up clean.

Check for any remainders in Settings > Apps > Apps & Features, and also in each of your browser's Extensions or Add-On's as shown here: https://community.box.com/t5/How-to-Guides-for-...

Then check for damaged System Files: https://www.lifewire.com/how-to-use-sfc-scannow...

If it cannot repair them see Step 10 here to continue: http://answers.microsoft.com/en-us/windows/wiki...

If you want to keep Malwarebytes as an on-demand scanner then you can disable its Real Time trial version in it's Settings > Accounts tab.

I hope this helps. Feel free to ask back any questions and let us know how it goes. I will keep working with you until it's resolved.

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