Microsoft KB Archive/260712

= Blank Screen When Resuming with MS-DOS Prompt Active =

Article ID: 260712

Article Last Modified on 1/27/2007

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APPLIES TO


 * Microsoft Windows 98 Second Edition

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This article was previously published under Q260712



SYMPTOMS
When your computer resumes from Standby mode with an MS-DOS prompt active, the screen may be blank, and a blinking cursor may be displayed in the upper-left corner. The computer completes the resume operation and returns to normal when you move the mouse, or press any Windows shortcut key combination.

Additionally, any non-shortcut keys you press between the initiation and completion of the resume operation are sent to the program that is running in the command session window.



CAUSE
The resume operation involves a complex sequence of interactions between the currently active Virtual Machine (VM) and the following virtual devices: keyboard (VKD), mouse (VMOUSE), power (VPOWERD), and Configuration Manager (CONFIGMGR). The system broadcasts power-status messages to the installed drivers and running programs, and also initiates follow-up actions that wake up the user interface within the context of the active program. One of the critical items in this sequence is the necessity for full internal status and event checks of the system message queue, which occur as a natural consequence of normal window message processing by a program. This event sequencing stops because of the nature of the MS-DOS prompt.

The MS-DOS prompt runs within its own virtual machine (VM), which is separate from the system VM in which the visible window runs. This visible window is embodied in Winoldap.exe, which is a 32-bit Windows-based program with some specialized features that allow it to manage the interface for MS-DOS-based programs (such as the command prompt). It must reroute keyboard input directly to the client program VM. This means that Winoldap does not receive standard WM_KEYUP and WM_KEYDOWN messages, which is why the resume sequence stops. However, it does receive and handle the remaining assortment of window messages, including WM_MOUSEMOVE, WM_SYSKEYUP, WM_SYSKEYDOWN, and so on, which is why moving the mouse or pressing a Windows shortcut key combination causes the system to completely wake up. This also accounts for the fact that all other keyboard activity initiated between the initiation and completion of the resume process is directed to the MS-DOS-based program.



WORKAROUND
To complete the resume operation, move the mouse, click one of the mouse buttons, or press any of the following key combinations. Note that for these items to work, the corresponding check box must be selected on the Misc tab in the MS-DOS Prompt properties:
 * ALT+TAB
 * CTRL+ESC
 * ALT+PRINT SCRN
 * ALT+SPACE
 * ALT+ESC
 * PRINT SCRN
 * ALT+ENTER



STATUS
Microsoft has confirmed that this is a problem in the Microsoft products that are listed at the beginning of this article.

Keywords: kbpowerman kbprb KB260712

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