Any ad you see trying to get you to call to repair, fix, etc. are scam ads for criminals. Are you continuously seeing those types of ads?
The best security add-on for Firefox is NoScript....used it for many years. It takes some time to learn to use it properly but it is well worth it.
NoScript Security Suite :: Add-ons for Firefox
Next would be an ad blocker such as Adblock Plus as often even legit ad servers are compromised and show the criminal ads.
Adblock Plus :: Add-ons for Firefox
Adblock Plus - Chrome Web Store
You can block third party cookies from installing. Those are ad and tracking cookies.
How to disable third-party cookies in all major web browsers
Once you have done the above run CCleaner to remove the existing third party cookies.
Use CCleaner to remove Temporary files, program caches, cookies, logs, etc. Use the Default settings. No need to use the
Registry Cleaning Tool...risky. Pay close attention while installing and UNcheck offers of toolbars....especially Google.
After install, open CCleaner and run by clicking on the Run Cleaner button in the bottom right corner.
CCleaner - PC Optimization and Cleaning - Free Download
The best security program is between your ears....your knowledge of how to avoid adware and malware through safe browsing and installation of software.
“Every atom in your body came from a star that exploded and the atoms in your left hand probably came from a different star than your right hand. It really is the most poetic thing I know about physics...you are all stardust.”― Lawrence M. Krauss
A 1792 U.S. penny, designed in part by Thomas Jefferson and George Washington, reads “Liberty Parent of Science & Industry.”