I use Nortons Security Deluxe....
It does everything and so far no issues.
It is
not free.
I shopped around looking at stores, from Symantec {Nortons company}, amazon & anyplace else reputable I could find.
I knew what program I wanted, I was shopping $.
Lowest price is where I went.
I ended up paying $24.99 for a year for 5 users to be protected.
In my house that does all the computers, not on my cell phone as I do nothing on that where security is needed.
I still have left over "users" should I need some...
For $5 per computer though I think a bargain for peace of mind.
There are other protection programs that are said to not bog down a computer as Nortons does....
My computer is so fast as it is I would not know the difference anyhow.
I have always had this brand from my very first computer purchased and never had issue with compromise or problems.
That keeps me a happy returning customer.
As for ads...use a ad blocker and wipe your cookies cache file clean.
After you "clean" you will need to relog in everyplace but the tracking that is plaguing you with ads undesirable should be gone.
I also ran a ad blocker and that worked great too, except here.
This site sent me cranky messages daily.
Your problem though is because of tracking malware {cookies}....
If you can selectively choose what to keep and what goes...perfect otherwise, clean sweep.