Question : Dell Vista error code 7B, hang at black screen after login, factory retsore

I am trying to get Latitude E4300 to boot into Vista
Business. A week ago it started exhibiting the following problem (suspiciously after
some Windows automatic updates): It will get to the Login screen, but after I select
a user and type in the password, it goes to a black screen with a responsive white
mouse cursor. It does not proceed, even after hours: it does not respond to CRTL-
ALT-DEL, and the HD light shows minor periodic activity. Same behaviour in Safe
mode, and with another user profile. During booting in safe mode there is a short
pause at crcdisk.sys.

I have attempted the following:
1) run dell diagnostics from F8 boot menu - (passed)
2) removed HD and attached to another system and run chksdk /f /r /b  (no errors or
bad sectors found)  I was able to view the HD contents and copied off the user data
files.
3) run Startup Repair from the F8 Dell menu (no change)
4) disabled all non-essential devices in BIOS to see if hang caused by hardware
failure (no change)
5) Restored system state to 2 different earlier restore points (no change)
6) when I try to boot from a Bart XPE CD I get a BSOD and Error Code 7B ( I was
trying to create a new user profile in case all the existing ones were corrupt)

Do you have any suggestions, short of full re-install of the OS?

How do I restore the HD to factory state? I don't have any separate Dell OEM
recovery CD's with Vista Business or Dell drivers. When I boot using F8 I can get
the "System Recovery Options" menu, but it does not include a choice "Dell
Factory Image Restore". It has only:
Startup repair
System restore
Windows Complete PC Restore
Windows Memory Diagnostic Tool
Command Prompt

From a cmd prompt using Diskpart I can see Disk 0 with 3 volumes:
Volume 1 X: Recovery 2GB
Volume 2 C: OS 231GB
Volume 3 no letter   FAT 125MB Hidden

Answer : Dell Vista error code 7B, hang at black screen after login, factory retsore

i did not suggest to run a repair; but to test the disk
since it does not boot, you can use the ubcd which has the diags :  http://www.ultimatebootcd.com/
you can also rewrite the whole disk with it, but be sure to backup the data first !