would the following idea/info help?
If safe mode is not an option then since you can boot part of the way it may be an idea to use the WinXP recovery console. To start the Windows Recovery Console, use any of the following methods: Start your computer by using the Windows Setup floppy disks or the Windows CD-ROM. At the "Welcome to Setup" screen, press F10 or press R to repair, and start the Windows Recovery Console.
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Once at the recovery console you can use the following commands to help fix the problem.
BOOTCFG /Rebuild : this rebuilds the xp boot configuration.
CHKDSK drive /p /r :The chkdsk command checks the specified drive and, if necessary, repairs or recovers the drive. The command also marks bad sectors and recovers readable information.
FIXBOOT drive name:Use this command to write the new Windows boot sector code on the system partition. In the command syntax, drive name is the drive letter where the boot sector will be written. This command fixes damage in the Windows boot sector. This command overrides the default of writing to the system boot partition.
FIXMBR device name: Use this command to repair the master boot record (MBR) of the boot partition. In the command syntax, device name is an optional device name that specifies the device that needs a new MBR. Use this command if a virus has damaged the MBR and Windows cannot start. You can obtain the device name from the output of the map command. If you do not specify a device name, the MBR of the boot device is repaired, for example: fixmbr \device\harddisk2. If FIXMBR detects an invalid or non-standard partition table signature, FIXMBR prompts you for permission before rewriting the MBR. FIXMBR is supported only on x86-based computers.