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Troubleshooting Windows 95 Using Safe Mode
Article ID: 156126 - View products that this article applies to.
This article was previously published under Q156126
IMPORTANT: This article contains information about editing the registry. Before you edit the registry, you should first make a backup copy of the registry files (System.dat and User.dat). Both are hidden files in the Windows folder.
Starting Windows 95 in Safe mode can help you resolve issues that occur when you start Windows 95 normally. These issues include (but are not limited to):
Starting Windows 95 in Safe mode bypasses the current real-mode configuration and loads a minimal protected-mode configuration, disabling Windows 95 device drivers and using the standard VGA display adapter.
If the issue does not occur in Safe mode, you may be experiencing a conflict with hardware settings, real-mode configuration issues, incompatibilities with legacy Windows programs or drivers, or registry damage.
For a description of the events that occur when you boot Windows 95 in Safe mode, see the following article in the Microsoft Knowledge Base:
(http://support.microsoft.com/kb/122051/EN-US/ )How Windows 95 Performs a Safe Mode Start
PREPARING TO TROUBLESHOOT IN SAFE MODEThe procedures in the following sections describe steps to troubleshoot configurations in which Safe mode resolves an issue with Windows 95. Many of these troubleshooting steps require changes to system configuration files. These changes are not intended to be permanent; they should be used as techniques for isolating the conflict that resulted in an issue with the normal configuration.
The examples in this article assume that Windows 95 has been installed in the Windows folder on drive C. Adjust the syntax as required by your configuration.
Before you begin making changes, you should create an Emergency Boot Disk (EBD) if you do not already have one. You can use the EBD to restart the computer and edit the configuration files if any changes you make cause the computer to hang.
To create an Emergency Boot Disk, follow these steps:
Troubleshooting the Windows 95 configuration files may require that the files be edited. You can use the MS-DOS text editor or System Configuration Editor to edit these files.
To use the MS-DOS text editor, type edit.com at a command prompt, and then choose the Open command on the File menu to open the file you want.
To use System Configuration Editor, click the Start button, click Run, type sysedit in the Open box, and then click OK. Click the file you want to edit on the Window menu.
TROUBLESHOOTINGThe Safe-mode troubleshooting steps are broken into the following sections:
ISSUES WITH THE REAL-MODE CONFIGURATIONWindows 95 bypasses the Config.sys and Autoexec.bat files in Safe mode. A real-mode device driver or terminate-and-stay-resident program (TSR) loading in one of these files may conflict with Windows 95, leading to the issues you are experiencing during a normal boot. The following steps can help you determine if this is the case.
Test the Real-Mode Configuration
If the issue persists, the contents of the Config.sys or Autoexec.bat file may be at fault. You have determined that a conflict exists with the real-mode configuration, and you should perform a clean boot of the real- mode configuration.
Clean Real-Mode BootWindows 95 does not require a Config.sys or Autoexec.bat file. These files are necessary only for backward compatibility. If you do not need these files, rename them and restart your computer. For example, rename the Autoexec.bat file to Autoexec.bak, and rename the Config.sys file to Config.bak.
If the Config.sys and Autoexec.bat files are required, perform a clean boot of the real-mode configuration with the required drivers. To do so, follow these steps:
WINDOWS 95 COMMAND-LINE SWITCHESStarting Windows 95 with command line switches is an effective method for isolating issues with your configuration. The switches should be used for troubleshooting only; use the information to modify your existing configuration and eliminate the conflict.
Description of Command-Line Switches/D - Used for troubleshooting when Windows 95 does not start correctly.
F - Disables 32-bit disk access. This is equivalent to disabling the hard disk controller(s) in Device Manager.
S - Specifies that Windows 95 should not use ROM address space between F000:0000 and 1 MB for a break point.
V - Specifies that the ROM routine will handle interrupts from the hard disk controller. This is equivalent to the System.ini file setting of "VirtualHDIRQ=FALSE."
X - Excludes all of the adapter area from the range of memory that Windows 95 scans to find unused space. This is equivalent to the System.ini file setting of "EMMExclude=A000-FFFF." If this switch resolves the issue, you may have a conflict in the upper memory area (UMA) that requires an Exclude statement.
NOTE: Each of the System.ini file entries referenced above belongs in the [386Enh] section of the System.ini file.
WINDOWS CONFIGURATION FILES AND PROGRAMS STARTED AUTOMATICALLYWindows 95 includes several methods for loading programs automatically. Starting in Safe mode prevents any programs from being started automatically.
Windows 95 includes a Win.ini and System.ini file for backward compatibility with legacy programs and device drivers. Upgrading a previous installation of Windows 3.x to Windows 95, as well as adding software, can lead to conflicts within the Windows configuration files.
Determine If Issue Is Related to Program Starting at StartupLoad Windows 95 by booting to a command prompt and starting Windows 95 by typing win, holding down the SHIFT key for the duration of the boot. This prevents any programs from loading automatically at startup.
If the issue is resolved by preventing programs from loading at startup, investigate the following possible sources:
The Winstart.bat FileThe Winstart.bat file is used to load TSRs that are required for Windows- based programs and are not needed in MS-DOS sessions.
For more information concerning the Winstart.bat file, see the following article in the Microsoft Knowledge Base:
(http://support.microsoft.com/kb/134402/EN-US/ )Some TSRs Moved from Autoexec.bat to Winstart.bat During Setup
The Win.ini FileThe "load=" and "run=" lines in the [Windows] section of the file can start programs automatically. See the following section for more information.
The Startup GroupIf the issue is resolved by bypassing the Startup group, remove each of the programs from the Startup group individually to isolate the problem program.
The Run Key in the RegistryWARNING: Using Registry Editor incorrectly can cause serious problems that may require you to reinstall Windows 95. Microsoft cannot guarantee that problems resulting from the incorrect use of Registry Editor can be solved. Use Registry Editor at your own risk.
NOTE: For information about how to edit the registry, view the Changing Keys And Values online Help topic in Registry Editor (Regedit.exe). Note that you should make a backup copy of the registry files (System.dat and User.dat) before you edit the registry.
You can prevent programs from loading by removing the program's string from the following registry key:
Programs may also being loading from the following registry key:
Test Windows Configuration FilesTo test the Windows configuration files, follow these steps:
(http://support.microsoft.com/kb/140441/EN-US/ )Creating a New System.ini File Without Third-Party Drivers
PROTECTED-MODE DEVICE DRIVERSSafe mode disables all protected-mode device drivers for Windows 95. Testing for incompatible components and resource conflicts can be conducted by disabling the protected-mode device drivers in Device Manager.
Removing Protected-Mode Device Drivers to Isolate Conflicts
133240If you determine that a Windows 95 protected-mode device driver is incompatible with your hardware, contact the hardware vendor to determine the availability of new drivers.
(http://support.microsoft.com/kb/133240/EN-US/ )Troubleshooting Device Conflicts with Device Manager
CHANGING THE VIDEO DRIVER TO STANDARD VGA DISPLAY DRIVERNOTE: If you followed the directions in the previous section ("Removing Protected-Mode Drivers to Isolate Conflicts"), you changed the display driver to VGA, and you can skip to the next section. Disabling the display adapter sets your video to the VGA driver.
Safe mode starts Windows 95 with the VGA display driver. To determine if the issue you are experiencing is related to your video driver, change to the VGA driver for testing purposes.
NOTE: To ensure a safe return to your previous configuration:
REGISTRY DAMAGEWhen you start Windows 95 in Safe mode the registry is read minimally. Damage to the registry may not be evident when running in Safe mode; it may be necessary to replace the existing registry (System.dat) with a backup to determine if the issue is caused by a damaged registry. To troubleshoot a damaged registry, follow these steps:
If the issue is not resolved, restore the original registry. To do so, follow these steps:
(http://support.microsoft.com/kb/139437/EN-US/ )Windows 95 Emergency Recovery Utility
(http://support.microsoft.com/kb/135120/EN-US/ )Configuration Backup Tool for Backing Up the Registry
IF THE PROBLEM PERSISTSIf the troubleshooting steps outlined in this article do not resolve the issue, the issue may be related to one or more of the following items:
If you have enough free disk space, install Windows 95 to an empty folder (such as a Win95 folder). For information about how to do so, see the following article in the Microsoft Knowledge Base:
142096If this resolves the issue, your previous installation may have included components incompatible with Windows 95. Consult your computer's documentation or manufacturer for information about modifying the CMOS settings and the availability of BIOS upgrades.
(http://support.microsoft.com/kb/142096/EN-US/ )How to Reinstall Windows 95 to a New Folder
Article ID: 156126 - Last Review: November 15, 2006 - Revision: 1.1