Please help me resolve the following problems whenever I turn my laptop on."Data Execution Prevention; Name Userinit Logon Application; Publisher: Microsoft Corporation" orThe instruction at "0x005f0687" referenced memory at "0x005f0687". The memory could not be "written"andWindows has closed Task Manager. Thank you!

Hi rein1143,Did you make any software or hardware changes on your machine prior to these issues?For Data Execution Prevention error, you may turn off DEP & check if the issue persists. Data Execution Prevention (DEP) is a security feature that helps prevent damage from viruses and other security threats by monitoring your programs to make sure they use system memory safely.For more information, refer this link.You receive a "Data Execution Prevention" error message in Windows XP Service Pack 2 or in Windows XP Tablet PC Edition 2005For the error code "0x005f0687”, you may run a memory diagnostic on your machine & check.For Task Manager error, you may check in event viewer for any error codes.How to view and manage event logs in Event Viewer in Windows XPHope the information helps. Please post back and let us know.RegardsDebleena SMicrosoft Answers Support EngineerVisit our Microsoft Answers Feedback Forum and let us know what you think.

You should not be getting a Data Execution Prevention error from anything to do with userinit unless your system is afflicted with malicious software or sometime in the past you have been tinkering with the DEP settings in XP.Have you ever in the past had any kind of DEP errors in XP?Data Execution Prevention (DEP) messages mean that Windows feels threatened by some program running on your computer, so it shuts it down. This is actually a good thing since Windows recognizes the threat and is trying to prevent further damage. Advice to disable DEP on a system to prevent DEP errors instead of actually fixing the problem is also usually short sighted advice. You need to fix the problem that is causing the DEP error, not just disable the DEP error reporting mechanism or make the program immune from DEP scrutiny. That is not fixing the problem. DEP is there for a purpose.Of course, XP should never feel threatened by any of it's own programs unless there is something wrong with them.Are you unable to boot and login to your system at all?Please provide additional information about your system:What is your system make and model?What is your XP Version and Service Pack?Describe your current antivirus and anti malware situation: McAfee, Symantec, Norton, Spybot, AVG, Avira!, MSE, Defender, ZoneAlarm, PC Tools, Comodo, etc.Was the issue preceded by a power interruption, aborted restart, or improper shutdown? (this includes plug pulling, power buttons, removing the battery, etc.)Does the afflicted system have a working CD/DVD drive?Do you have a genuine bootable XP installation CD (this is not the same as any Recovery CDs that came with your system)?Fill in the blank: My system was working fine until: ____________________________________________.Do, or do not. There is no try.I need YOUR votes and points for helpful replies and Propose as Answers. I am saving up for a pony!

Hi jose,Thank you so much for your answer. My pc starts with a disc check, then will proceed to the Application Error, "The instruction at 0x00600687". The memory could not be "written". Click on OK to terminate the program or Click on CANCEL to debug the program".after clicking "OK", it will proceed to " The instruction at "0x005f0687" referenced memory at "0x005f0687". The memory could not be "written"after clicking OK for so many times, it will proceed to the Log On to Windows windowthis time, i can see the background of my desktop but there is no any icon on it, instead, "Data Execution Prevention- MSWindows" is shown.after closing this window, i will see nothing but the clean desktop.what will I do?My OS is XP Pro, Windows 2003, SP2; i uninstalled my norton antivirus; my battery needs replacement because it is not charging anymore; I have the genuine bootable xp installation CD.My system was working fine until I let my colleague borrowed it from me.Thanks!

You only answered part of the questions.Microsoft support for Service Pack 2 ended in July - is there some reason you have not made it to SP3 yet?First, you need to get your desktop working, then you can resolve your potential malware issue.Click past or OK what ever error messages presented and see if you can just get to an empty desktop displaying just your background image.From your background image, press CTRL-ALT-DEL and open Task Manager.Look at the Processes tab and if the explorer.exe Process is not running, launch it. Click File, New Task and in the Open box enter:%windir%\explorer.exeClick OK and see if you get your desktop back.If explorer.exe is already running in the Processes tab, it is likely the object of the affliction and may need tobe replaced (which is not difficult).If you see that the explorer.exe process is already running in Task Manager, highlight the explorer.exe process then clickthe End Process button to terminate it, and launch a new explorer.exe process as indicated above.If things look okay now, your system is still not fixed, but it should be useable enough so now you can fix it.Please report back with the missing answers from before and if you get your desktop working.Do, or do not. There is no try.I need YOUR votes and points for helpful replies and Propose as Answers. I am saving up for a pony!

That sounds messed up!You have a working CD drive, yes?When your system starts up with the check disk, are you prompted to cancel the check disk by pressing any key (and what happens when you do).Microsoft support for Service Pack 2 ended in July - is there some reason you have not updated to SP3 yet?First, you need to get your desktop working, then you can resolve your potential malware issue.Click past or OK what ever error messages presented and see if you can just get to an empty desktop displaying just your background image.From your background image, press CTRL-ALT-DEL and open Task Manager.Look at the Processes tab and if the explorer.exe Process is not running, launch it. Click File, New Task and in the Open box enter:%windir%\explorer.exeClick OK and see if you get your desktop back.If explorer.exe is already running in the Processes tab, it is likely the object of the affliction and may need tobe replaced (which is not difficult).If you see that the explorer.exe process is already running in Task Manager, highlight the explorer.exe process then clickthe End Process button to terminate it, and launch a new explorer.exe process as indicated above.If things look reasonable now, your system is still not fixed, but it should be useable enough so now you can fix it.If your desktop is working, are you able to get on the Internet?Please report back with the missing answers from before and if you get your desktop working and if you can get on the Internet.Do, or do not. There is no try.I need YOUR votes and points for helpful replies and Propose as Answers. I am saving up for a pony!