I just went through the exact same issue. After installing the latest round of MS updates to Windows 8.1 I started having problems. My computer would boot up to the login screen, but as soon as I logged in I would just get a black screen with the mouse cursor. I couldn't make anything work except Ctrl-Alt-Del. If I even tried to Start a Task Manager a box would flash up for a second and then go black. All I could do then was Sign Out and reboot. Fortunately, I was able to boot into Windows Safe Mode. I then on a whim decided to go into Services and disable both Start8 and WindowBlinds. Then, after rebooting, I searched these forums and found this post. After reading about the WindowBlinds issue, I enabled Start8 and that is running fine. If I enable WindowBlinds again I just get a black screen at login again and have to go through disabling it all over again. I verified that I do have WindowBlinds 8.05 installed as well. Looking through the Event Logs I see a bunch of Explorer.EXE Errors whenever I tried to log in with Window Blinds enabled.
Faulting application name: Explorer.EXE, version: 6.3.9600.17039, time stamp: 0x53156588
Faulting module name: unknown, version: 0.0.0.0, time stamp: 0x00000000
Exception code: 0xc0000005
Faulting application name: Explorer.EXE, version: 6.3.9600.17039, time stamp: 0x53156588
Faulting module name: unknown, version: 0.0.0.0, time stamp: 0x00000000
Exception code: 0xc000041d