When starting Windows the blue screen of death appears with the following error, preventing the computer from loading correctly: ?0X0000008E (0XC0000005, 0X804EEF91, 0XF326A7DC, 0X00000000)?. The computer will boot correctly into Safe Mode, but upon investigation no System Restore points exist preventing the roll-back of the computer into a previous state. This error may be the result of a series of mistakes which I recently made on the computer. The problem started after I installed Norton Internet Security 2007 without removing the old internet security software. Following the installation of Norton Internet Security the computer restarted and booted normally to the Windows XP logon screen. However, when I attempted to logon as a user the blue screen appeared with a STOP message. I then started the computer in Safe Mode and used System Restore to restore the computer to the day earlier than the installation. The restore operation was successful, and Windows opened normally and everything worked correctly. However, when I started the computer the next day the same blue screen appeared again. I assumed the problem was caused by Norton Internet Security and contacted them for technical advice. I wonder whether this could have been caused when I attached a new portable hard drive to the USB port before starting the computer. Symantec advised me to perform a clean boot (i.e. start the computer with no non-essential processes and services) and then uninstall and reinstall their product. I made another mistake during the clean boot, as I misunderstood the directions where they asked me to hide all Microsoft programs from the Services tab before unticking the rest. I did not see the hide box and I thought that I had to untick all the Microsoft services, which I did. Upon restarting the computer the same error occurred again. Having restarted the computer the same stop error happened again. Then I started the computer in Safe Mode and used the Symantec instructions to re-enable the previous disabled services and restarted the computer. I was able to connect the portable hard drive and backup my files while working in Safe Mode. However, the blue screen still appears when starting the computer in Normal mode. Is there any way to fix this problem?

First, thank you for the very comprehensive explanation of the problem being experienced on your computer, as this greatly assists in diagnosing the root cause of the issue. To begin, there are several reasons this problem may have occurred. It is almost a given that the problem was triggered by the installation of Norton Internet Security, since the problem occurred immediately after this product was installed on the computer. As you mentioned, the most likely cause was that the old internet security software was not uninstalled prior to the installation of Norton Internet Security. From experience, security products can be especially sensitive to conflict as they are both attempting to act on the same resource (i.e. the computer network and internet connection). To this end, you should never run multiple internet security packages on the computer simultaneously (this same advice also applies to other security software which run in the background of the computer, such as antivirus software). An alternative explanation is the problem does not relate to a conflict between the old and new software, but instead is due to a completely different conflict between Norton Internet Security and another piece of software on the computer, or there is something that is conflicting between Windows itself and the Norton product. In either case, the blue screen error appearing at the moment is a very serious problem, and it will be quite difficult to determine the root cause of the error.

Since you have already tried disabling all non-essential services on the computer, yet the problem continued, the problem is unlikely to be caused by a conflict between Norton Internet Security and a service running on the computer. The next possibility is a conflict between Norton Internet Security and a process running on the computer. To determine whether this is the cause, boot into Safe Mode and go to the “Start” menu > “Run” then type “msconfig” (without the quotes) and click OK. In the System Configuration Utility window that appears, click the “Startup” tab. Write down all the processes which are currently enabled (ticked) and then disable all the processes by clicking “Disable All”. This will prevent those processes from loading on startup, allowing us to determine whether any of those processes are causing the problem. Click OK to close and save the changes, and then restart the computer into Normal mode and check whether the problem persists. If not, one of those processes is causing the problem. In this case, go back into the System Configuration Utility and enable one of the startup processes which were previously enabled, then click OK and restart the computer. Continue this process until the problem re-occurs, and you will know the process causing the problem.

However, if this does not solve the problem I would propose that the problem is serious enough that your best solution is to complete a reinstallation of Windows. Even if you could resolve the problem I would still be concerned that this error indicates that something happened to the computer which may cause future stability issues, and in the long-term a full reinstallation would be the best option. You mentioned that you could successfully boot into Safe Mode and backup your data to an external hard drive, which makes the reinstallation process easier as you have been able to easily backup your important data. As the reinstallation process will result in all data being lost from the computer, I strongly suggest that you have a secondary backup. Also, double check that all essential data has been backed-up, as once you commence the reinstallation process all data will be lost on the computer and will not be recoverable.

After the reinstallation has completed and you have a fresh installation of Windows, I suggest that you install Norton Internet Security as one of the first third-party applications you load onto the new installation. This will ensure that you are protected from any threats on the new installation, and also make sure that this software can be loaded prior to any other software which may cause a conflict with Norton Internet Security.