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Missing Operating System After Setup Restarts Your Computer

This article was previously published under Q134708
This article has been archived. It is offered "as is" and will no longer be updated.
When you are installing Windows 95, you may receive one of the following error messages the first time Setup restarts your computer:
- Missing Operating System
- Invalid System Disk
When you receive one of these error messages, the computer no longerboots from the hard disk.
There is an incorrect value in the Partition Boot Record (PBR) on thehard disk. Any computer with a mis-match in the number of read/write headsreported by the Partition Boot Record and the system BIOS will likely havethis problem.

If there is a mismatch in the reported number of read/write heads, theC:\Setuplog.txt file contains unequal numbers on the following line:
FSLog: BIOS Heads=:64:, BootPart Heads=:64:
To correct this problem, follow these steps:
  1. Restart your computer using the Emergency Startup Disk.
  2. Use the SYS command to transfer system files to the hard disk. For example, if the Emergency Startup Disk is in drive A, type sys c:.
  3. Remove the Emergency Startup Disk from the floppy disk drive and then restart your computer. Setup should continue.
If you do not have an Emergency Startup Disk and cannot obtain one, startyour computer using a Startup disk from your previous operating system(such as MS-DOS). Use the SYS command to transfer the system files to thehard disk, restart the computer, and then run Windows 95 Setup again.
This issue is known to occur on Leading Edge Fortiva 5000 computers. The PBR on Leading Edge Fortiva 5000 computers returns a hexadecimal valueof 40 heads. The actual value is 20.

For additional information about the "Invalid system disk" error message,see the following article in the Microsoft Knowledge Base:

Error Message "Invalid System Disk" After Setup Reboots


Article ID: 134708 - Last Review: 12/04/2015 11:49:16 - Revision: 1.1

Microsoft Windows 95

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