Windows 10 freezing after startup. Please help

What's the 7-character "service tag" number on your Alienware 17 R2 laptop?

You installed a new hard drive and then did a clean install of Windows 10 in it, and your laptop is still freezing after starting up and loading the desktop?

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Do you hear fans running inside laptop? You can try using "can of air" to blow inside laptop grates and then a v acuum to clean from outside afterwards might make a difference.

Dell Alienware 17 R2 Laptop
It came with Windows 8.1. 64-bit, but is now running Windows 10 Home 64-bit.

From what you said in post #3, it appears the update process after the initial install is causing the freezing issue.
Did you install a third-party antivirus app, or are you using its built-in Windows Defender Antivirus app?
Which Windows 10 "Version" and "OS Build" did you initially install?
Note: Fall Creators Update Version 1709 OS Build 16299 will be released in a few days.

I doubt the freezing issue is being caused by overheating.

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Since Safe Mode runs ok it might be something in startup causing this. Do a search for "startup" and choose "see what processes automatically startup when you start Windows"....tell us what's enabled there (you can do this in safe mode).
The other thing you should do is run checkdisk R which you can start in safe mode also:
https://www.tekrevue.com/tip/fix-hard-drives-chkdsk-windows-10/