Antiviruses and Firewall are cool, but common sense triumphs them all. If you're looking for a combo, try Avast + Malwarebytes, I use Bitdefender + Malwarebytes.
It works for me, haven't been infected yet.
When it comes to Windows Updates, install them ASAP, it's not like you will be in trouble, the odds of you get infected by drive by downloads are low IF you use common sense, but it doesn't hurt to be safe.
Regarding encryption, always use it, if you're living in US, it does hamper your speed, also it's good practice to encrypt your portable devices such as Phones, Laptops. Keep one system as in Desktop which acts as the central server and keep important stuff in it, have two local backups and then an online cloud backup, I recommend backblaze, Dropbox is great for keeping things in between devices.
Always use a password manager, I prefer Lastpass, but you can try Keepass and other goodies. It's a lot better than making up passwords and storing them on Notepad, which I did.
When it comes to flashing your Laptop BIOS, make sure you have a backup BIOS from the manufacturer, they usually give you a recovery BIOS and do read up on the manual. My HP Laptop fucks up the BIOS updates due to the SSD for some reason, hence I end up recovering and trying again. So, keep that in mind.
When it comes to picking the right parts for the Computer, always plan it in stages, if you're buying a new system and don't really have enough money, then buy a good foundation as in good PSU, good casing, good motherboard that allows you to upgrade later on, I cannot stress how important this is.