You don't say much about your PC so this is only speculation. Since you apparently had Windows 7 on the PC previously, I'll assume you have an older system.
Last August I updated my older PC to Windows 10 Pro 64-bit and had no end of trouble with it freezing the boot process just before the Windows 10 lock screen should have appeared, and after a while the BSOD screen appeared with a DPC_WATCHDOG_VIOLATION error. This always occurred after I replaced the default NVIDIA driver that Windows Update would download after a clean install of the OS. The latest NVIDIA driver for my system that I was attempting to use at the time was 398.82-WHQL. That was a red flag and I suspected my issue was a problematic Graphics Card Driver. This was confirmed when I opted to install a previous NVIDIA driver, 398.36-WHQL after the OS install and experienced no issues. As it turned out, there were two driver releases issued by NVIDIA that exhibited this problem: 398.82-WHQL and 399.07-WHQL. The issue was acknowledged in the Release Notes for 399.07, "NVIDIA graphics driver may not install correctly on certain Core 2 Duo/Quad systems. [2312325]". As of driver 399.24-WHQL and later, NVIDIA appears to have resolved this particular issue and I've had no further problems. My system specs are below. If this seems like your problem, you can view the thread on NVIDIA Forums at https://forums.geforce.com/default/topic/1066456/geforce-drivers/can-t-boot-windows-with-398-82-installed/ or search their forums further. Good luck.
System specs:
Gigabyte GA-EP45-UD3R(rev. 1.1) w/ F12 BIOS
Intel Core2 Extreme QX9770 @3.2GHz (this is an unlocked, quad-core, non-HyperThreaded CPU running at stock speed)
8GB (4x2GB sticks, Dual Channel) Crucial Ballistix Sport PC2-6400 800MHz Non-ECC DDR2
Gigabyte GeForce GTX 1060 WINDFORCE OC 6GB
HP Pavilion 22bw Monitor (1920 x 1080 @60Hz native)
On-board Realtek ALC889A codec, HD Audio
Windows 10 Pro x64 ver. 1803 (OS Build 17134.22