HP Pavilion dv7 graphics issue

[Timtamtum]

I'm currently trying to troubleshoot this HP Pavilion DV7-6c23cl laptop for a family member, but it's got a bizarre issue. About 80-90% of the time, it will POST and boot, but just before it gets to the login screen, all peripherals (screen, keyboard, mouse, fingerprint scanner) go dead. Not the "I haven't loaded everything" dead, dead.

Safe mode works completely fine 100% of the time, and sometimes the computer will boot without a problem, leading me to suspect a software issue. But I can't pinpoint anything, because any driver issue with the GPU or the mouse or what have you wouldn't affect the other peripherals.

Anybody had a similar issue? All the other threads I've seen concerned a black screen immediately out of POST, but I get the "Starting Windows" screen just fine before everything blacks out.

Specs of the computer (in case it matters):
Operating System: Windows 7 Home Premium 64-bit (6.1, Build 7600) (7600.win7_gdr.150318-1623)
Language: English (Regional Setting: English)
System Model: HP Pavilion dv7 Notebook PC
BIOS: InsydeH2O Version CCB.03.61.09F.1C
Processor: AMD A8-3520M APU with Radeon(tm) HD Graphics (4 CPUs), ~1.6GHz
Memory: 6144MB RAM
Available OS Memory: 3562MB RAM

 

[BadAsAl]

Boot in Safe Mode, then use msconfig to disable all services and startup items. Reboot. It should boot just like it did with safe mode.
The key now is to figure out which startup item or service is causing the issue... Go back into msconfig and enable half the services. Reboot and see if it boots ok. If it boots ok, go back into msconfig and enable half of the remaining disabled services. Keep doing this with the services until either you have enabled all the services and it boots ok or it fails to boot. If it fails to boot then you know the service causing the issue is in the last group you enabled and you can start narrowing down. If the services are not the issue then you need to do the same thing with the startup items.

 

[Timtamtum]

Disabled everything, boot still fails. Safe mode works fine but default boot still wacko. Clarification: boots successfully but no display after the Windows logo finishes its animation.