I work in IT Tech support (Hardware & Networking) so have a fair bit of knowledge and experience but this one has really got me stumped.
I got a tower running XP Pro on IDE 0 with DVD RW and on IDE1 I got 2nd data HDD. Both are Maxtor drives. It’s a fairly old machine but serves its purpose until recently.
The problem started when I accidently left my USB flash drive in and forgot when I booted. My legacy USB devices were set as priority in boot sequence so I got message "Operating System not found" since there is no OS on my pen drive. Instantly I realised I had left my USB pen drive in and removed it then rebooted fine that time.
However since then I still get the OS not found please read on as I have tried everything. I now have my legacy USB support turned off and have removed it from the boot sequence. AND no I do not have my USB flash drive still plugged in. I have even removed my PCI USB2 cards and now only use the onboard USB2.
PROBLEM: My BIOS is loosing my hard drives intermittently and I get standard message “Operating System not found” I pretty much think I have tried absolutely everything to fix it. Here is a list of some of the things I have done.
Checked and swapped CMOS battery (twice) but the date and time always remain correct as well as settings it is only the drives that go missing
Checked all mobo and HDD jumpers, swapped out IDE cables numerous times plus a new PSU for good measure
Tried all BIOS settings methodically
Run XP recovery console for following commands:
I have reinstalled XP both repair and clean install.
I suspected one of the HDD was failing so I ghosted both drives to new drives and run chkdsk on the new ones.
I have run extensive Maxtor HDD diagnostic tools on the drives all say they are fine apart from 1 invalid partition so I ran partition magic and made my primary partition active.
I ran fdisk formatted and repartitioned my boot HDD then installed XP again
My HDDs are set to auto find in BIOS but I do not know the manual settings as they are not written on the drive casing. I would like to manually key in the heads, cylinders, LBA etc rather than leave on auto and I found Maxtor manual for drives but only LBA settings listed and it was a huge tech manual for it
I flashed my BIOS to the newest available (it is an old Phoenix BIOS on a emachines mobo for Hewlett Packard) I want to get hold of previous version and flash it back but none are available anywhere on net they are listed but dead links only currant link is live (I spent many days searching)
Now then its not all doom and gloom but my only saving grace is that, at least, I can get the machine to boot. I have to switch PSU off and unplug power to all drives then boot. When it fails I switch power again, plug all drives back and F1 to BIOS setup then it finds drives I exit saving changes and it boots to XP with both HDD and DVD drives. Next time I boot I get same OS not found error and have to repeat the whole thing again.
Please someone come up with something new I am loosing my hair rapidly!