Ok two ways to get back and boot again, use a backup and restore it to os hdd partition or disk if no partition, assuming is recent and not lose lots of data. If recent and don't want to lose data but accept upset xp os settings back to as was when first installed os. Boot with xp os install cd and get to the stage where after it says press F8 to continue installing. There is a line that can repair the os which is far better than the first chance to repair os. This one will take files of cd it needs and after will be able to boot into your os drive again.
(xp cd repair deatil explained: With xp cd you get two changes during install to repair os. Fisrt from memory is when run the cd on first or second screen. The one you need is when you can choose to install xp. Or just after that and is the one to use. Forget the first it is hopless. Of course maybe you backup using xp and have a floppy disk for that. Never used it but guess would be same as using a third party backup tool. I would use that since settings won't get changed with xp cd repair. My menory for this is hazy because i use third party tool for backup and restore. Not used xp cd for many years to do this.)
But this is not finding the actual reason why it happens, which i'm sure is a system os file. In dos MHDD, victoria show all hdd as good after bad sector scans and smart scans. It's not boot.ini, ntdlr or mbr at fault but something else since i have tried replacing and repair for those.
As i now have a disk image .img of after it has happened with no boot. I will next mount the .img and compare it to the system right after repair. To show which files are different, looking more at those critical os files which shouldn't change in size normaly
Though be sure this isn't a BOOT.INI, NTDLR or MBR problem first. Which there are remedies are in this thread for how to cure them. Even a net search for a simple NTDLR fix disk can be found, also for MBR and boot.ini problem fixing.
I now go and try find out the cause of this, as every so often it will happen again. So far i know it is not bad hdd or devices on pc. Neither any virus, trojan or malware affected file.
I have for a while on and of played with floppy disks using win98se and dos7 disks. So i can get the os to do this when i need it to with using the win98se floppy boot disk install image file. By description here you may think of the answer to this, do test this first before writing so no to annoy others of a unworkable sollution.
I have made a disk to emaulate a bad floppy disk, one that has a bad sector so cannot read, write or format. After made bad sector on disk that is a full data disk. I select to delete a file on which this bad sector is. Disk grinds away and reports cannot be deleted. So next i select all files on floppy disk and select to delete them. This time disks grinds away and soon the xp explorer crashes. That is everything on the desktop including taskbar, folders, icons - all dissapear. For a few moments nothing, until explorer comes back to normal desktop screen. That is as the desktop is after a reboot, no folders open etc. The floppy disk has stopped take it out of the drive.
Now look in ":C\documents and settings\your-user-folder\locale\temp\" you will see some files that are named clusters, recovered etc. Look at those the contents is a list of what is on the floppy disk. Delete those files (not to trash bin) and reboot pc. For me pc will post and remain on black screen with flashing cursor. Even on a pc which gives on screen status (there is no status). Onboard bios status (mothboard diagnostic) all shows ok and should be booting.
Something on the win98se floppy disk has changed a xp system file so it doesn't boot. That is boot disk win98se OEm if someone else like to try this http://www.bootdisk.com/bootdisk.htm
with tools to make bad floppy disk sectors for a file on disk such as winhex and others. For ease of finding, it is one of the files on the floppy. IO.SYS, COMMAND.COM, CONFIG.SYS, MSDOS.SYS etc
Next i will compare the a backup os image to the backup image of after this occurs. That is, after restored os to hdd and will be bootable (not yet booted to os so files change least as possible). Will check this in dos may take a liitle while as need to find a tool to mount images in dos (ntfs) then a tool to compare each byte in dos on those mounted hdd images. Got any ideas which tools incase i am still looking by time you read this.
Edited by pippy, 18 February 2011 - 09:22 PM.