Here's a prob that I eventually fixed, but I'd really like to know why it became such a nightmare...... 1) PC had 2 drive partitions (both FAT32), owner wanted C formatted and XP re-installed. 2) Formatted C with floppy boot disk and then booted the XP disk to install. 3) Install completed without problems (or so I thought), re-booted PC (bios set back to boot floppy first, HD second), but PC wouldn't boot - 'invalid system disk' (no there wasn't a floppy in the drive !!) 4) Tried fixboot in rec console - no go 5) Tried repair - same problem 6) The PC *would* boot into XP ok providing cdrom was set as first boot device and the XP disk was in. 7) Checked boot.ini - all fine. 8) Owner wasn't bothered about saving D drive, so I used latest fdisk - deleted both partitions/created new (diff sized) ones and re-formatted - XP re-installed again - now I get 'No Operating System' !! 9) Removed HD and slaved in my machine - found ALL the original files (on C & D) *still* in place and original partition sizes despite fdisk and format 10) At some point during the above I tried using fixmbr and XP disk's own utility to format - still no go. 11) Found a thread on this forum re the same probs, and it transpired that the ONLY way out was to perform a 'low-level format' (write zeros) using Maxtor Powermax. 12) Used the prog, re-installed XP and all ok !! I have since read something about XP's MBR being different to other MBR's ?? I have installed XP dozens of times but never seen/heard of this prob before. Can anyone enlighten me as to what went wrong here ?? Thx

That was a MBR (master boot record) problem, I hade similar problem when installed Linux and the formated and installed windows xp... did not work... so I couldnt delete de linux partition to install xp in the right way. So I have to low level format disk to erase all the MBR data... or... running in DOS: a:\fdisk /mbr hope this help!

Could have been a boot sector virus. I have seen them survive and FDISK first hand. Even on a system running FAT32 I still would not use a 98 Boot Disk. I would just use the options during the install process to delete/create and format partitions. KTTD

Thx for the replies - at one point I did use the XP disk to try and format, and I also tried fdisk /mbr from the boot floppy - both to no avail. The MBR would not release it's grip whatever I tried... very strange !!

I did read that you used fdisk. Same problem will occur if the primary partition is deleted, then recreated and not set to active status. Even though the installation of the new operating system will complete, it will not boot and give an "No Operating System" error message. Takes me back to Win 9x days. Had the same thing happen to me. Best not to use fdisk when working or installing XP. XP can be installed directly from the CD.

is it possible that the hard disk was disabled and something you did re-enabled it? if your hard disk is disabled in the BIOS and you run the xp install cd, you can still install, but when you reboot first time it detect an OS