KSOD (Black Screen of Death) issues can be caused by many different issues, the quickest and easiest method of fixing this is running system restore if possibly. This error is a kernel level error and are very tricky for the end user to fix, even if it is possible because this error cannot always be fixed. I think 'K' in ksod stands for kernel.

Things i have tried

• chdsk
• chkdsk /r
• could be windows event log service
• virus hook on shell
• black screen virus
• faulty update - remove recent updates
• run system restore

• disable all services and reboot (this did not make any difference)
• disable msconfig items manually

• try permission reset with SubInACL command line thing and that batch file in console
• try reset registry permissions
• try adding the prevx fix url in to the start up group thing in the registry so it autoruns itself

• add a beep or 2 after it has finished a script set to autorun
  http://forums.whirlpool.net.au/archive/564510
  http://blogs.msdn.com/b/tims/archive/2006/11/02/windows-vista-secret-10-open-an-elevated-command-prompt-in-six-keystrokes.aspx
  http://www.woodwardweb.com/technology/windows_vista_t.html
  http://www.sevenforums.com/tutorials/11841-run-administrator.html

• "C:\Program Files\Internet Explorer\iexplore.exe" "http://info.prevx.com/download.asp?GRAB=BLACKSCREENFIX"
• try injecting updated graphics drivers
• check HKLM\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Winlogon\Userinit   make sure it says
  C:\Windows\system32\userinit.exe
  it could be as subtle as a . on the end ie C:\Windows\system32\userinit.exe.
• is it loading a corrupt hibernation file. delete the hibernation file to remove this issue
• malware scan

Other Things To Try

• How to fix KSOD aka the black screen of death on window - YouTube
• try use last known good configuration
• system restore (use a bootable disk to do this if necessary)
• when black screen appears try tapping shuft 5 times, or ctrl-alt-del and then run task manager etc.. oe explorer.exe
• Black Screen (KSOD) Vista Solutions « Bertie Baggio's Wonderland
• SubInACL

What Worked For Me

KSOD is cause by incorrect permissions from a failed update usually. Fix the file permissions and the update will complete allowing windows to run.

• scan with malware and comodo CIS - remove all shit
• then add everyone to C:\ (of the client drive) permissions and apply to all (i also include administrators)
  or
  use a permissions utility to restore permissions such as the one from tweaking.com or SubInACL
• put back in client machine when you can read the files

when i put it back in the client machine a windows update carried on and might explain why i could not run sfc or indeed why the PC failed.

Links

• Black Screen (KSOD) Vista Solutions « Bertie Baggio's Wonderland - This also mentions that they had success by repairing the permissions using icals. Multiple solutions here and worth a read.
• How to fix KSOD aka the black screen of death on window - YouTube - I have not tried anything on this video
• VISTA - Black Screen white mouse pointer - suggests the icals solution here