"Missing operating system" on boot up...

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nick3318

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Jul 10, 2006
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Hey guys, I've been working with this PC for a few months now no problems. But i just got home from a LAN that i went to and when i tried to boot for the first time i got a "Missing operating system error".

The first thing i figured was that i must have knocked a drive unplugged during the transport of my PC. I opened the pc up but couldnt find anything wrong. I also noticed something else...usually when i start up it will show a quick splash screen of my hard drives that i have connected...now it just says it cant detect any. The weird thing is when i go into BIOS they are still listed under the SATA devices.

Any tips? Im hoping this is just an easy fix and i didnt physically damage anything while carrying around my PC :/

Here are some specs:

Windows Vista Ultimate

Asus Maximus Formula

2 x 150 GB Western Digital Raptors in RAID 0




UPDATE: I tried using the repair function on the Windows disc. I couldn't find my operation system on the list of OS's to repair, even after loading the drivers i used to set up the raid. So i just hit next and tried the "Startup Repair" function anyway. It worked for around 15 minutes before saying it could not repair the operating system.
 
NEVER run a windows repair on a drive that says missing os/missing system registry ect. you must repair the file structure or else cause damage to os.

to do this boot your vista cd you then need to get in a command prompt and run chkdsk /r

 
It is possible that sata configuration was different form default before you first installed your Vista and your bios reset 2 default. try 2 change sata settings in bios. and chkdsk /r . hope it not 2 late :). And please install Acronis or Ghost, it saved my ass more than one's. :)
 
Hi guys,

I know I'm a bit late to this discussion but I just ran into this problem myself. My problem was caused by something which wasn't listed in the discussion yet.

It all started within Windows... I was installing a developer version of the SQL server from a external USB drive. And when the installation was over it wanted me to restart the computer, so I did, only to see the "Missing operating system" message on bootup... Panic!

Of course my first reaction was panic... Where's my operating system?! So I quickly popped the Win7 RC disc into the dvd drive, hoping it could repair the problem. But when the repair tool booted, the OS list was empty. "Hmm, that's odd" I thought... So started my laptop and browsed the internet for a solution and I found this discussion. After a few seconds I realized the cause... It was the newly plugged in USB drive.

First, being lazy, I thought I could just alter the bootup devices and sequence in the bios. But to my surprise that didn't help so I had to unplug the drive completely, but when I did, the OS came right back up. Phew! 😉

Hope this helps if somebody else get caught of guard by this problem.

Kind regards,
Johannes
 
WOW, JohannesH I owe you big!!

That is exactly what the problem was for me. I didn't change anything at all in my settings -- didn't move my computer or anything -- but when I turned it on this morning, I got the "missing operating system" message. I am running Windows 7 RC1.

My first reaction was to panic, but then I decided to google "windows 7 missing operating system" and came across this thread. I saw JohannesH's comments and looked down at my computer -- sure enough, there was a thumb drive that I had left plugged in.

It seems for some reason that at least with certain types of thumb drives, Windows 7 detects them and tries to mount them during boot up -- hence the "missing operating system" because there is of course no OS loaded on your thumb drive!

I was about 30 seconds from a heart attack when I thought I was going to have to spend my morning formatting my computer. Unplugging the thumb drive worked. THANK YOU!!!
 
i have the same problem but when i put my vista cd in it doesn't say fix or anything just load. And when i do load it after it's done the screen just goes black.... help
 
hey how do you unlug a usb ? I'm 17 and I don't know what to do, my comuter keeps giving me a black screen and saying Missing operating system , please help.

~Dustin

p.s. I don't have a recovery disc, is that bad or should I have one ?
 
I just experienced the same thing:

Windows 7 Pro 64bit
ASUS P6T LGA 1366 Intel X58 ATX Intel Motherboard

After installing SQL 2008 I was prompted to reboot. I did and received the 'Missing Operating System' message. Checked the bios and found the RAID configuration had changed. I did not change the configuration myself so I'm not sure if it was the SQL install or something with the motherboard. I changed the configuration back to what it should be and the operating system loaded - phew.
 


I've just come to this site after googling 'Missing operating system' and have seen I had the same problem! - I left my USB memory stick in and phone on charge over night. So it will b something like this u unplug - then start puter again - plug in only when puter is up and running.
 

I'm still new on the understanding of computers but this was my problem as well apparently. I had my RAID setup disabled somehow on reboot. TYTY for posting xD.
 
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