Guide - HAL.DLL is corrupted or missing, what do I do?

[Sovereign]

Disclaimer: This is something that is entirely my original work, as I had to do this to fix not one but two PCs here @ college.

Legal Disclaimer: This is from my own personal experience (that I just had), it's something I couldn't find anywhere and figured out myself. I offer this "AS IS" with no warranties or guarentees, express or implied. You use this advice at your own risk and accept sole responsibility for anything resulting from your use of this information.

Whew! Now that the boring stuff is over, on to fixing the problem.

You boot your PC, perhaps because you upgraded something or upgraded to Windows XP. You get an error:

Originally Posted by Windows XP Hates You

Windows could not start because the following file is missing or corrupt:
<Windows root>\system32\hal.dll.
Please re-install a copy of the above file.

If you've tried all of the following methods, and none of them work, read on...
1. Just restart, Windows can be dumb sometimes.
2. CHKDSK /F /R (the file could have been damaged due to a sudden power-off, but I doubt this could happen. This is just what any power user reflexively does when it looks like data could be damaged).
3. Boot into Safe Mode (or any of the other options that you can get with F8 like Last Known Good)
4. Edit the BOOT.INI file (this fix assumes BOOT.INI is corrupt, when it is not, HAL.DLL is actually damaged.) This is suggested as a fix in an article from InformationWeek, but having found it in a Google search about corrupt HAL.DLLs, I found that it does not help if HAL.DLL is truly corrupted.
5. Use the Repair Option in Windows XP. In theory the Windows install should be able to find the damaged XP installation and fix it. However, in this case it simply did not find any valid Windows installations, fixed BOOT.INI files nonwithstanding.
6. Expanding HAL.DLL from the XP installation disc or copying HAL.DLL from another computer. The HAL.DL_ file would not expand, even though I had used BartPE to delete the original HAL.DLL. From my understanding of HAL.DLL, it is dynamically generated from a base template file (the one on the XP CD) upon installation. Therefore, unless the hardware in your machine is very similar to the one of the machine you are trying to repair, chances of copying and pasting a HAL.DLL and having it work are slim to none. (If this is wrong and someone can in fact point me to a case where this worked, please tell me as 3+ hours of Google searches seemed to vindicate the idea that HAL.DLL cannot be dragged and dropped.)

So, you're just about to format right? There is a way around this, that I discovered after accidentally damaging a friend's hard drive with PartitionMagic (that app is the DEVIL do not use it to "merge" partitions that were created in the factory before Windows was installed, it crashed two friend's computers and I got stuck fixing them).

You need a CD of Windows XP. I do not believe it matters which Service Pack or whatnot. Any will do. You are going to reinstall Windows (regardless of version, you can install Windows XP next to another installation of Windows XP, it's dual-booting the same OS) to regenerate HAL.DLL.

Now, follow these steps.
1. Boot from the CD and start the installer
2. Choose to install onto the already formatted partition with the unbootable Windows, but opt to leave the existing filesystem and any other OSes alone. Choosing this will require you to create another folder for Windows to avoid writing over the existing installation (that it somehow sees now but not when the Repair "Scanning for previous installations of Windows" is run, argh!) I usually call the new folder "WINXP."
3. Install Windows as you would normally, you'll need a Product Key but you can actually use your personal key on someone else's computer with no danger to you losing it or being accused of piracy, I'll explain this later.
4. Boot the NEW Windows XP install. Do not "Activate" or "register," you're going to be deleting this copy of Windows from the machine if all goes well.
5. Edit the BOOT.INI on the hard drive from the original installation of Windows with the corrupted HAL if you messed it up like I did and had four OS entries in it, none of which worked. This usually happens when you try to use the method outlined in the InformationWeek article repeatedly and it does not work.
6. Go to C:\WINXP\system32\hal.dll (where "WINXP" is the folder you installed the second copy of Windows XP) and copy it from the new Windows to C:\WINDOWS\system32\hal.dll (or wherever you installed Windows XP originally, I use "WINDOWS" but some people use strange folder names for their XP) and overwrite any file there. The new hal.dll is uncorrupt and newly regenerated. The file is specific to each machine's hardware configuration and we needed to rebuild it. The installer did that for us with the new installation.
7. Try rebooting your computer to see if you can get into your OLD Windows installation. If you can, congratulations!
8. DELETE the "WINXP" folder (or wherever you put your new Windows install).

Now PayPal me some money for all this effort...
j/k! If anyone runs into this situation, they will know how to deal with it.

But it didn't work! I still can't boot! What should I do?
First of all, breathe. Did you choose the right OS to boot from (chances are if you didn't edit BOOT.INI you still have a pointer from your install of Windows that you used to regenerate hal.dll and then deleted once you thought you were finished. Try a different OS choice and if it boots, go to the System control panel, Advanced, Startup and Recovery, click the "Edit" button so you can mess around with BOOT.INI.

Sample BOOT.INI for XP Pro

Originally Posted by Microsoft

[boot loader]
timeout=10
default=multi(0)disk(0)rdisk(0)partition(1)\WINDOW S
[operating systems]
multi(0)disk(0)rdisk(0)partition(1)\WINDOWS="Micro soft Windows XP Professional" /NOEXECUTE=OPTIN /FASTDETECT

NOEXECUTE is for Data Execution Protection, and this setting means only core Windows apps will be DEPped.

If you have any questions, just ask them here.