I wonder if it would make a difference if I disconnected it?
That's the first thing that I would try. I'd also unplug any other peripherals that are un-needed, including any wireless dongles (Bluetooth, wifi, keyboard, mouse dongles) and attach a wired keyboard and mouse just to cover all my bases.
F8 will not get you into safemode on a Windows 10 machine and getting into safemode on a machine that will not boot is a bit tricky and convoluted but if you are willing to try, here's how....
Boot into the Windows Recovery Environment either by using a Recovery Disk that you've made, or the original Installation Media.
Choose Repair, Advanced Troubleshooting, Command Prompt and type
bcdedit /set {default} bootmenupolicy legacy
reboot your PC and tap the F8 key (no shift key required) and it should work for you as it has in the past.
To return your boot menu to normal
bcdedit /set {default} bootmenupolicy standard