Hi there Gail and welcome.
Can you tell me exactly when you see this message and if your still able to use your computer for other things?
ok, then your not infected, its the sites that are saying this, else you would be getting this message on every site.
Best to clear the cache though. To do this, in Chrome click on the three bars in the top right and click on Settings.
Then click on show advance settings at the bottom of the screen
Then click on Clear Browsing Data, select from the beginning of time and click again Clear Browsing Data.
This will then ensure the cache is cleared.
I can also do these steps for you, and have made a request via Additional Services. This is optional, and if you choose to do this, I can, with your permission, remote into your computer while you watch and do all these steps (and deal with any problems that arise during them) for you. Or if you do not choose to take this service, we can continue here. This is no problem at all. Just let me know please.
Else If you have any problems, or would like any additional information or assistance, please do not hesitate to let me know.
And if you can take a second to rate my service by clicking one of the stars at the top of the screen then submit, that would be greatly appreciated.