How to remove unwanted ads on my blog and wordpress dashboard?

Is your blog hosted on WordPress.com?

Even if it was hosted on WordPress.com, WordPress.com does not run ads in the Dashboard.

I’d start by deactivating all plugins. If that resolves the issue, reactivate each one individually until you find the cause.

If that does not resolve the issue, try switching to the Twenty Fourteen theme to rule-out a theme-specific issue (theme functions can interfere like plugins).

If neither of those work, please note that it’s possible for the ads to be caused by malware or a virus, but more often it is due to a browser extension or toolbar that you may have installed in your browser.

These sites have further explanation and suggestions for eliminating the ads:

https://onecoolsitebloggingtips.com/2012/09/14/bloggers-beware-of-adware/

https://blog.wikimedia.org/2012/05/14/ads-on-wikipedia-your-computer-infected-malware/