Question How do i know if my pc is infected or my wifi hijacked?

[LilWhiteChris]

The older iv got the more worried iv become over privacy and just how safe my pc is.

I Just dont understand how you KNOW if you have been infected with a virus or the likes, How would you tell? and is there a way to check or does simply running the programs listed below ensure im safe?
I also worry my internet has been Hijacked and someone is watching everything im typing and doing on my pc... is there anything you can do to check that your internet/router is still secure?

Things im currently doing:
1)Have Malwarebytes free that i run every so often.
2)Have Avast free antivirus that i run every so often.
3) Iv changed my Router ID/Name and Password and made it Hidden. (In the UK you cant change the DNS on a sky router)

Avast is always telling me that I have 'Sensitive documents unprotected', 'Folders vulnerable to advanced ransomware', 'a basic firewall' and that im 'vulnerable to fake websites' and of-course they want me to play a subscription to rectify these things, im not sure if these things are actually anything or if its just a money making racket.

Any guides or advice welcome, im so paranoid, thanks.

 

[Lutfij]

As long as you don't visit suspicious sites and don't click on suspicious links, you're not in any imminent danger of divulging your contents or your network or your resources to anyone. If you're working with an additional router between the PC and the modem(Sky) then you're supposed to have firewall on it as well.

 

[mdd1963]

Free Avast obviously wants to sell you the add-on to encrypt your folders, files, or entire drive... (semi-scare tactic, but, designed for marketing their wares)