Iobit advanced systemcare is more of a spyware program than an antivirus, at least from my experience of using it.
If you aren't going to pay for a good antivirus like ESET, rather stick with windows defender.
Avast also seems to be junk. (I've seen many enterprise servers with Avast/kaspersky/mcafee and none of them were secure)
My second choice would have to be Bitdefender.
To remove them, just open up control panel and click on "uninstall a program"