All of these are related.
Primary root cause of the errors is the registry is corrupt which is located at

\windows\system32\config

and the registry is in MULTIPLE files

1. DEFAULT
2. SAM
3. SECURITY
4. SOFTWARE
5. SYSTEM

The following topic are all related to registry errors:

System32\config file corrupt
http://www.techspot.com/vb/topic21417.html

System32\config\System File corrupt
http://www.techspot.com/vb/topic59287.html
http://www.techspot.com/vb/topic53755.html

missing file windows\system32\config\system
http://www.techspot.com/vb/topic74906.html

oops; xp fails to boot
http://www.techspot.com/vb/topic74708.html
my fix to avoid reformatting http://www.techspot.com/vb/showthread.php?p=439868#4

Recover your data before you reformat!
http://www.techspot.com/vb/topic76094.html


Microsoft Solution:
http://www.techspot.com/vb/topic14234.html#4

With a copy of \Windows stored elsewhere (or a backup of just that directory),
all of this could have been avoided