Today, I installed Zorin OS latest edition. As soon as I turned my computer(laptop) on, the hp and zorin os logo appears and flickers endlessly and doesn't boot. Then I press the power button for 10 secs to switch the computer off. But what's odd is that when I again turn the laptop on, it takes me to boot menu and when I select the "Run Zorin OS" option, it boots successfully. But after I shutdown and again try to boot, the same problem appears and the problem appears again in the same pattern. What could be the problem? I am also posting my system specs and all info.
Just for good measure, update your system to Zorin OS 17.1.
Just running a normal update suffices, no need to re-install or run the Zorin Release Upgrader.
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Welcome to the Forum!
The latest Version is Zorin 17.1 not Zorin 17. but that is no bigger Problem. Do like @anon2532484 wrote update the System and then look if it still happens.
Do you have that Flickering only when the Machine boots or in the normal Desktop Run too?
Thanks for the warm welcome. It flickers infinitely while booting, but after closing and again booting it works fine, as mentioned in the question.
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You might test if using nomodeset grub parameter helps...
Tried it. Didn't help. Still facing the same issue. Plus when I updated to Zorin os 17.1, I am facing refresh rate and scaling issues. I am thinking about switching back to windows 10 or maybe Linux Mint.
You can remove the parameter if it is not helping. Be sure to run sudo update-grub after.
The best option is the one that works best for you. 
I see in your screenshot you are using Intel 620 graphics. Do you have a dedicated Nvidia card installed (You may have had prime-select set to on-demand)?
Are you using Fractional Scaling?
Have you tested Zorin OS on Xorg / Xserver?
To do this, from the login screen, click the gear icon (click "sign in as another user" if you cannot see the gear icon appearing, then click the gear icon, then return to logging in as yourself) and choose Zorin Desktop on X
Have you tested how Zorin OS 16.3 Lite performs?
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Maybe it is a Problem with the Graphics Driver.
Did you tried Linux Mint before? If yes, did You had there the same Issues?
I did not install linux mint, but did try it. Didn't like the ui.
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Yes, I can understand that. Theoretically you could install another Desktop Environment but that is another Topic. But for a Try if You there have the same flickering Issues it should be enough.
One Thing for Zorin: How are your Display Settings? I mean Resolution and Scale Factor.
Yes, about that... Ever since I updated to Zorin OS 17.1, my windowing system is automatically switched to x11 which I don't like at all. Earlier when I had just installed the OS (Zorin OS 17), I just had the flickering issue, now I have scaling issues too. I've tried all the ways listed in this forum to switch back to Wayland but all in vain. The cogwheel at the login screen doesn't appear. Now I'm stuck with 2 issues.
Img 1: Invisible Cogwheel blocking access to wayland setting. And yes I did try the config file setting from terminal to enable wayland but all in vain.
Img 2: Scaling Issues, when I scale to 125% or any%, the screen displays distorted image and inadequate and incorrect scaling.
The first one is a still image, but in reality, the whole screen flickers endlessly at this point and I have to force shut down the laptop.
To see the Gear Icon You have to click on Your Profile. Then appears the Password Field and then appears the Gear Icon in the bottom right Corner. Not before. On Your Picture is only Your Profile to see.
Because of the Scaling: When the Fractional Scaling is turned off do You have the Flickering too? Or is it then normal?
As mentioned, I have tried all the methods listed in the forum to make that cogwheel appear, but succeeded in none. I did click on my profile and tried the other several methods like clicking on not listed and editing the config file. As for the second part of your question, the flickering in the booting process has nothing to do with the scaling. At this point, I am thinking about returning to windows, since I feel like everything in Linux needs to be fixed. And clearly Zorin OS is not for beginners!
This is a perfectly normal human feeling. Interestingly, I felt this often on Windows OS.
Getting strange "has performed an illegal operation" or "error 0x00000008" and trying to troubleshoot it was like pulling teeth. You serach all over the web and get suggestions of commands in cmd prompt and regedit changing the DWORD value...
I notice your refresh rate is set to 77Hz. Are you using a 4k monitor?
When you don't have the Option for Wayland maybe it could be that Your Hardware isn't compatible with Wayland and so you only have X11.
At this Point I would thick that the Flickering could be a Problem with Your Graphics Driver or with Your Display/Monitor and the normal Refresh Rate of them. The 77Hz that I see on your Picture ... comes that from the Drivers Settings? Or is this default? I mean, it is not 50/60Hz or 100/120Hz. It is an in-between Thing.
No, I'm not using a 4k monitor. When I installed Zorin OS 17, my windowing system was Wayland and refresh rate was 60Hz which is the max I think my laptop would support( It is a cheap one). But after updating to 17.1 windowing system changed to x11 (which I don't like) and refresh rate is 77Hz, which I can't change now.
"It could be that Your Hardware isn't compatible with Wayland and so you only have X11" I don't think so, because I was using Wayland when I installed Zorin OS 17, it changed to x11 after I updated to 17.1
Hmm ... Maybe the Update makes something wrong. One Thing that You could try is a fresh Install with Zorin 17.1. But this is maybe not the best Solution. Could You try this Command in the Terminal:
sudo apt reinstall zorin-os-desktop