So, for a couple of weeks now I've been having trouble installing Windows XP Service Pack 2.  I kept on getting registry errors during the install process, finally ending off with an “Access is Denied” message, thus, ending the installation.  However, after a lot of searching, I found the following solution, which actually works, as compared to all of Microsoft's solutions.

(UPDATE -- September 19, 2008.  This page has now had over 76000+ page views.  Hope you're all still benefiting from this solution! )

If this solution helps you, please considering donating money to help me pay my medical student tuition (now debt), of over $50,000.  Thanks!

You can donate by clicking here.

Do the following:

1. Download and install subinacl from:
http://www.microsoft.com/downloads/details.aspx?FamilyID=e8ba3e56-d8fe-4a91-93cf-ed6985e3927b&displaylang=en

2. Download and install this file:

Download our SP2 Registry Fix here for $5.00CAD -- Your order helps put me pay off my medical school debt!

3. Run SP2 Installation

Alternatively, you can follow these directions:

1. Download and install subinacl from:

http://www.microsoft.com/downloads/details.aspx?FamilyID=e8ba3e56-d8fe-4a91-93cf-ed6985e3927b&displaylang=en

2. Create a file named reset.cmd in C:\Program Files\Windows Resource
Kits\Tools folder.

3. Edit the reset.cmd file with the following content.

subinacl /subkeyreg HKEY_LOCAL_MACHINE /grant=administrators=f
subinacl /subkeyreg HKEY_CURRENT_USER /grant=administrators=f
subinacl /subkeyreg HKEY_CLASSES_ROOT /grant=administrators=f
subinacl /subdirectories %SystemDrive% /grant=administrators=f

subinacl /subkeyreg HKEY_LOCAL_MACHINE /grant=system=f
subinacl /subkeyreg HKEY_CURRENT_USER /grant=system=f
subinacl /subkeyreg HKEY_CLASSES_ROOT /grant=system=f
subinacl /subdirectories %SystemDrive% /grant=system=f

4. Enter into CMD prompt.

5. Enter the following commands one at a time and click Enter.

cd\
cd "C:\Program Files\Windows Resource Kits\Tools"
reset.cmd

6. Let the program do it's work, then run the SP2 installation.