DOCUMENT:Q71211  08-OCT-1999  [win95x]
TITLE   :Windowed MS-DOS Apps Revert to Full Screen in Windows
PRODUCT :Microsoft Windows 95.x Retail Product
PROD/VER:WINDOWS:3.0,3.0a,3.1,3.11
OPER/SYS:
KEYWORDS:

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The information in this article applies to:

 - Microsoft Windows versions 3.0, 3.0a, 3.1, 3.11 
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SUMMARY
=======

While running an MS-DOS application in a window, Microsoft Windows may switch it
to full screen if an MS-DOS critical error occurs. Typically, the critical error
will be a disk error, but there are other causes as well.

The common critical MS-DOS errors are:

 - attempting to access a floppy drive with no disk

 - attempting to write a file to a write-protected floppy disk

 - attempting to access an unformatted floppy disk

When an MS-DOS critical error occurs, MS-DOS is unstable until the critical error
is resolved. To maximize stability, Windows switches the application to
full-screen text mode. This is by design and there is no workaround. Press
ALT+ENTER, after the error is resolved, to switch the MS-DOS application back to
the windowed display mode.

MORE INFORMATION
================

Switching Between Full Screen and Windowed Display Modes
--------------------------------------------------------

The "windowed" display mode of MS-DOS applications is only available in 386
enhanced mode. There are three actions that can be performed to run an MS-DOS
application in a window or full screen:

1. Select the desired mode in the PIF Editor.

2. Press ALT+ENTER to toggle between the two modes.

3. Select the desired mode from the MS-DOS application's system menu:

   a. Start the MS-DOS application in question.

   b. Press ALT+SPACEBAR to display the system menu.

   c. Select Settings (press T).

   d. Select Windowed (press W).

   e. Press ENTER.

MS-DOS Int 24H Critical Errors
------------------------------

The critical error handler is a function of interrupt 24H. A complete listing of
the MS-DOS Int 24H critical errors are listed below.

Error Code
Hex     Dec  Description
---------------------------------------------

00H      0   Write-protect error
01H      1   Unknown unit (invalid drive number)
02H      2   Drive not ready (no disk or driver door open)
03H      3   Unknown command requested
04H      4   Data error (CRC)
05H      5   Bad request structure length
06H      6   Seek error; move to requested cylinder failed
07H      7   Unknown disk format
08H      8   Sector not found
09H      9   Printer out of paper
0AH     10   Write fault
0BH     11   Read fault
0CH     12   General, nonspecific error
0FH     15   Invalid disk change (MS-DOS version 3.0 or later)

Additional query words: 3.00 3.00a 3.10 3.0 3.1 3.11 win31 win30

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Keywords          :  
Technology        : kbWin3xSearch kbZNotKeyword3 kbWin300 kbWin300a kbWin310 kbWin311
Version           : WINDOWS:3.0,3.0a,3.1,3.11

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