Reseting the PC bios to defaults fixed the Stop 7B error
I had a PC that would not boot said there was a problem with hall.dll
So I tried to boot from the Windows XP CD and run the chkdsk c: /R command
but on booting from the CD the system crashed with a stop 7B Blue Screen of Death.
The fix for the stop 7B was to go into the system BIOS and restore to factory defaults,
and turn off the SATA Raid option which had been turned on when set to defaults.
Now I could boot off the XP CD and get to the Recovery Console by typing R at the first screen where it asks what you want to do.
I ran chkdsk c: /R
to try and resolve the corrupt C: drive
This fixed some errors on the hard disk but I still had the hal.dll error
I found this site which has steps to resolve the issue
http://pcsupport.about.com/od/findbyerrormessage/a/missinghaldll.htm
After performing step 4. Repair or Replace the boot.ini the bootcfg /rebuild
to repair or replace the boot.ini file the PC crashed again with the Stop 7B error