Installed Fresh OS after getting several blue screen errors

Notes to self: To install Fresh OS!
Things to do beforehand
1. Download an antivirus installer and keep it in a USB flash drive so that you can install the antivirus software before connecting the refreshed PC to the internet.

To save new OS in a USB drive (8 GB or more required),
Go to https://www.dell.com/support/article/us/en/04/sln299044/how-to-download-and-use-the-dell-os-recovery-image-in-microsoft-windows?lang=en

 and follow the steps of "Creating the USB recovery media" and then "Using the USB recovery media to install Microsoft Windows". When prompted to delete tpm, select delete.  This will take several hours.

After installing the OS, give it a plenty of time to set up, settle down, load, and ready to function. After initial sign-up, normal desktop screen will appear. Then;

1. Install antivirus software. Having more than one antivirus/malwarebuster/spiwarebuster is not a good idea. Don't forget to remove the media before doing the following steps because they may require restart. 

2. Settings --> Updates --> Check Windows Update. Let it download and install necessary updates. This may require restarting computer. Restart if necessary.
(After some search, I'm now not sure if it's really good. It is probably better to wait until prompted to install updates.)

3. Launch Dell Smart Assist (if not Dell, Windows key + R to start command prompt, then type devmgmt.msc ) to check if any drivers need updates.

4. Update everything. Restart if necessary. Give it plenty of time after restarting.
(After some search, I'm now not sure if it's really good. It is probably better to wait until prompted to install updates.)

5. Scan your PC using your antivirus software.

6. Go to Chrome store and install AdGuard AdBlocker and TrafficLight. Search "disney". If those are working properly, the official site of Disney should be the first one in the result, not other websites with ads. 

7. Download other softwares and use your PC normally.   

Notes on external hard drives:

You cannot remove (eject) it while the PC is on because external hard drives are considered to be what the PC should always be connected while it's on. So, leave it there and turn off PC, then disconnect the hard disc when the PC is off.

BUT do not turn on PC with the hard drive connected. This will lead to boot failure. No good.  

In short: turn off PC, disconnect hard drive, then turn on PC.