Jim
Two of the most popular web browsers are Internet Explorer and Google Chrome

although I suspect that it doesn't matter which one you use.
I assume that this is on a Windows computer, and I'm not sure it really matters which browser you are using.
I suspect that you have some sort of malware so ....
Go to this page
https://www.malwarebytes.org/mwb-download/and near the bottom click on 'download'
Do *NOT* accept a free trial of the 'premium version'
Once downloaded, install the program (making sure that you don't install any other free trials of stuff as you go) and then run a full scan of your system.
This may take quite a while, but when it has finished, do as recommended (probably quarantine or remove) then restart your computer and see how you get on.
Do let us know!
Good luck
