Help Question regarding virus alerts

[Android Question]

My wife has a Sprint Samsung J3 and has just called me regarding a message supposedly from Google mentioning she has 5 viruses and press this button to clean the device, tried to get out of the message and wouldn't let her. She uses this phone to make calls, sms and facebook. Yesterday she Googled about a-fib and the foods not to eat. I told her not to do anything until I check and to power the phone off.
Any suggestions please.

 

[The_Chief]

Sounds like a pop-up ad, courtesy of a less-than-stellar app on the phone. You can always turn the phone off and reboot it into Safe Mode to try and find the offender.

 

[lvt]

It seems like a pop-up from a web browser?

 

[dontpanicbobby]

It could be either. I run into them all the time surfing the web.
My favorite streaming video site says to ignore and close them if they pop-up.

If it happens while she's surfing the web have her look at the number next to the url box and if it's more than one, tap on the number and close the virus alert.

If it happens anytime like on the home screen do like lvt says.