Problem: Invalid Boot.ini or Missing Windows/System32/Hal.dll

When u switch on your computer or restart  Windows XP you receive either of the error messages below and cannot get into Windows..........
These errors are usually shown on a black screen with white writing and you cannot get any symptoms :

U receive one of the following error messages when attempting to boot into Windows XP:

• Invalid Boot.ini

• Windows could not start because the following file is missing or corrupt Windows/System32/Hal.dll

The above error message is usually caused by the boot.ini file not having the correct entries in it following the upgrade but can also be caused by a hardware problem or a missing or corrupt Ntoskrnl.exe file

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                          Solution

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Correct the Boot.ini file entries

• Insert u'r Windows XP CD and start your computer and watch out for the “Press any key to boot from CD” message.

• Press any key

• At the welcome screen press ‘R’ to enter the Recovery Console.

• At the recovery console, select your Windows XP installation and enter your Administrator password if requested

• At the prompt issue the following command and press ENTER:

bootcfg /rebuild

• When the bootcfg tool finds your Windows XP installation you will be asked the following:

 

[1] C:\Windows

Add installation to boot list?

(Yes/No/All) 

Note: The above text may look different for you depending on your installation type.

• Type Yes and press ENTER

• You will now be asked to Enter Load Identifier (message may be different)

• Enter the version of Windows XP that you own

Example: Windows XP Professional or Windows XP Home Edition

• You will now be asked to Enter OS Loader options 

• Issue the following and press ENTER:

bootcfg /fastdetect

• Remove your Windows XP CD, issue the following command and press ENTER:

exit

• Restart u'r PC

check this link for more support........Microsoft Expert Team