Форум поддержки Firefox

I went to a local website and ended up getting virus warnings, see photo. I doubt if it's real but I don't know how to get rid of the messages, or scan for the virus? I scanned with the Windows virus protection and the computer came back clean. I can and have turned the computer off and back on, no help.

Thanks

My computer was compromised And as a result I had to repair and re install my Microsoft operating system windows 10 pro. That procedure wiped out my Firefox browser and now I have no record. Is there a backup that the browser keeps on a cloud.