I have been setting up a Windows 7 workstation:
4 GB RAM
1 TB SATA hard disk
Core2 Duo CPU
Intel GPU of quite recent make
Windows 7 SP1 64-bit
About 1/3 of the times it boots up, it never reaches the login screen. Instead it shows a completely black screen with a cursor. The cursor responds to mouse movement, but there are no menus, and no response to keyboard input. I believe this is popularly known as the "black screen of death" or KSOD.
It also is extremely slow when it does complete the boot, and I am unable to figure out why. Process Explorer takes about 30 seconds to launch, for instance. There is no heavy disk activity, no high CPU usage, no unusual memory consumption; all drivers are installed, all devices are recognized, the Windows installation is brand new, and as far as I can tell there's no malware on it.
What are some probable causes, and how can I troubleshoot this thing further?