When I turn on my computer I got the following message " Window has detected a registry / configuration error. use: SCANREG to correct this error ".
(The computer don't start so I can't run " SCANREG " )
The computer then goes to the start screen with the following options
a) Normal
b) Logged ( \ Bootlog. txt )
c) Safe mode
d) Step-by-step-configuration
I tried " Normal " then it went to scan disk then to search for updated drivers on " A " drive but the result was not founded, I tried to have it search from the " CD rom " but there was no option for ' CD ' otherwise I would try booting from 'CD'.
Please advise what else can I do .?

Hello George, you need to run scanreg using your Windows XP setup CD, are you able to do this? Once the CD is inserted, just after the post screen the PC will automatically run this CD or give you a short period where you can press any key to start with your CD. XP Setup will then start, and you can press R to repair when prompted. This will take you to the recovery console where you can type in the scanreg command.

if it does not detect the cd you will need to set cd as first boot device in bios or use boot select both acess options are available at post if you see a full screen logo click tab to see the page. Bios setup will be del key or F2 or on a few occassions F1. Boot select could be F8 F11 or F12 asa rule

I reach as far as the setup screen and in BIOS I high light " from CD ram and press save and exit but it still don't boot.
( I placed the xp cd in the cd ram and then power up the computer but it still don't boot )

you you not get the press any key to boot from cd

This might seem like a silly question George, but when you selected the CD-ROM/RAM drive from within BIOS - Boot Order, you moved it to the very top of the list?