System: Desktop, Windows XP, WD Caviar Black hard drive. Ususally a 2TB WD Elements external HDD is connected to the PC.
Problem: When I returned from a short trip and tried to turn on my PC, after short boot sequence I got an error message "Cannot load operating system".
Tried solution: I plugged out all cables out of PC except mouse, keyboard, power cord and display cable, tried to boot, no success.
Then I downloaded Hirens boot cd tools to a USB flash drive and changed boot order in BIOS to load USB drive before HDD.
In Hirens tools I at first run WD diagnostics (quick scan) - it found the drive and returned no errors.
Then, as suggested in a thread on a similar issue, I tried to use "Boot windows (ntldr)" option from Hiren's menu - no success. I also wanted to try using another suggested fix - "fixmbr" - but couldn't find this exact option in Hiren's MBR tools and did not want to risk trying similar tools after reading that MBR fix can potentially wipe out all the contents of HDD.
Finally I loaded Hiren's MiniXP - and to my surprise I found, that in "my computer" it shows only 1 of the 4 partitions of my hard drive (the partition shown is not the one with operating system on it - which might explaing the "error loading operating system").
I have most of my files backed up, and I guess I can salvage anything I need from the 1 of the 4 partitions that I can see and acccess in MiniXP, but I would feel bad about loosing files and installled programms from the main (C) partition, as it will take me a long time to reinstall/tweak everything back...
Given that WD diagnsotics did not find any erros with my HDD, can this problem be solved, so that XP loads normally and I can acess all partitions (hopefully, without reinstall)? What are my next steps and/or what additional information should I provide.
Thanks a lot!
More about :error loading operating system partitions hirens minixp
From Hirens Mini XP I run a program called "Partition Find and Mount" - I scanned my hard drive, and the results were:
In "Visible partitions" it found my Data partition (D which I could also see from my Computer. In "Found partitions" it found my OS installation partition (C: before the crash). I mounted it and gave it a letter F:. Now in "My computer" I can see my old C: drive as an F: drive. "My computer" also shows C: drive, but as an empty partition - if I click "Properties" on it, it shows file format as RAW....
I will now backup all the neccesary files from my data partition and OS installation partition to an external HD. What should I do later to repair my computer (so that it loads normal XP, not only Hirens MiniXP). Could it be that simple as deleting " fake" C: partition and remaining partition F: (Which I mounted in "Partition Find and Mount" software) to C:?
Quick search found only data partition (after running to 16%), but when I afterwards run advanced search it found all the partitions, including the one with OS in it. Afterwards Testdisk analyzed partition's boot sector and found that boot sector is "bad". After running " Rebuild BS" option it was repaired. After restarting the computer I was able to launch XP from Hirens boot CD, everything is working.
The only thing left to solve is launching XP without Hirens boot CD - currently it gets stuck in the place where it would previously show "Error loading operating system". When I find a solution to this last issue I will post it here and close the topic.