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Ntvdm cpu illegal instruction??

Discussion in 'Software' started by LUNALIGHT, Jul 28, 2009.


    LUNALIGHT Private E-2

    Hi All,

    Some assistance would greatly be appreciated. I have had this Toshiba Satillite laptop for a year that is very rarely utilized except for work on those rare instances when I must travel. The OS is Windows Vista Home Premium. The last time I used the laptop I had no issues. I tried to fire it up the other day with no success.

    Upon start up the toshiba screen apears and it's down hill from there. I get the following system message:

    The NTVDM CPU has encountered an ILLEGAL INSTRUCTION
    CS:119b IP:0100 OP:ff fe3c 00 54 Choose "Close" to terminate the application.

    I also get a little dos window with C:\WINDOWS\SYSTEM32\LOGONUI.EXE in the title bar.

    I can think of nothing unusual or any issues that would create this problem.

    The machine refuses to boot from this point. I have selected both close and ignore only to find myself at a black screen. The results are the same in safe mode.

    I have to contact Toshiba to request a restore/reinstall disk as it did not come with one. Any assistance that can be provided would be greatly appreciated.

  2. samtal

    samtal Corporal


    LUNALIGHT Private E-2

    Thanks for your reply!

    Unfortunately at this juncture I am unable to run anything. Selecting close or ignore only closes the warning window and the command prompt. The computer boots no further and sits at a black screen. I have also attempted this is safe mode with the same results. :(
  4. NightFirer

    NightFirer Private First Class

    The process Windows Logon UI belongs to the software Microsoft Windows Operating System or logonui.exe by Microsoft Corporation (www.microsoft.com).

    Description: logonui.exe is located in the folder C:\Windows\System32. Known file sizes on Windows XP are 504,320 bytes (62% of all occurrence), 514,560 bytes.
    File logonui.exe is a Windows core system file. The program is not visible. File logonui.exe is a Microsoft signed file. logonui.exe is able to record inputs, monitor applications, manipulate other programs. Therefore the technical security rating is 2% dangerous, however also read the users reviews.

    Recommended: Identify logonui.exe related errors

    If logonui.exe is located in the folder C:\Windows then the security rating is 72% dangerous. File size is 59,904 bytes. Program has no file description. The program is not visible. File logonui.exe is located in the Windows folder, but it is not a Windows core file. File logonui.exe is not a Windows core file.

    If logonui.exe is located in a subfolder of "C:\Program Files" then the security rating is 64% dangerous. File size is 71,168 bytes. The application has no file description. The program is not visible. The application starts when Windows starts (see Registry key: HKEY_CURRENT_USER\SOFTWARE\Microsoft\Windows\CurrentVersion\Run, HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Run, HKEY_USERS\.DEFAULT\Software\Microsoft\Windows\CurrentVersion\Run). logonui.exe is not a Windows system file. logonui.exe is able to monitor applications.

    Important: Some malware camouflage themselves as logonui.exe, particularly if they are located in c:\windows or c:\windows\system32 folder. Thus check the logonui.exe process on your pc whether it is pest.

    The possible culprit is that you pick up a virus or malware some where.

    Since you can't do anything with it, suggestions would be try taking it in to a Reputable computer and have them repair it. which they would probably repair the installation for it Vista. Or if you have the install disk for the laptop you could run the install for Vista and repair it.

    But I would make sure a get a good anti virus and malware removal program. after you repair it

    LUNALIGHT Private E-2


    Thanks for the reply. Soon as the disks arrive from Toshiba, I'll be doing a complete reinstall.

    I run ccleaner and malwarebytes religiously, only thing I can think of is maybe one the "little people" in my house borrowed the off limits laptop with out permission.

  6. Wimpy1

    Wimpy1 Private E-2

    Hi Lunalight,
    I have the same exact problem that you do. Can you please tell me how you solved it. When I start up the computer and get the C:/windows/system32/logonUI.exe I am unable to type anything so I do not know how to reinstall Windows Vista without being able to type commands. Any help you or anyone else can provide will be greatly appreciated.

  7. patentable

    patentable Private E-2

    I've just solved the same issue on a Toshiba Satellite running Vista.
    Received the warning on boot - and was unable to log in.

    Was able to get to a DOS prompt via the restore disks. Go into C:\windows\system32 and rename loginui.exe to remloginui.exe. Go to the "X" drive, windows system32 directory and find loginui.exe and copy that file to C: - root directory and to C:\windows\system32. (not sure if this is necessary or an added step - but it worked). Both the original file and copy showed the same size, and subsequent scans showed my Satellite to be clean of viruses and malware. My Satellite when rebooted - was normal - with one exception - don't know if it's related - but windows update didn't list previous updates. Subsequent updates have been normal.
    Good luck.

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