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I had my computer running all night yesterday. This morning I wake up to find a message on the screen saying "Reboot and Select proper boot device or Insert boot media in selected boot device". When I reboot now I getting the same error. Not sure what happened all of a sudden to cause this issue. I have Windows 7 Ultimate installed on that machine.

Any idea why this happened and how I can fix it?

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1  
I am having the same issue. Going into BIOS settings only shows my DVD as a boot option. – Jean-François Gagnon Oct 1 '15 at 12:39

Guess what, I had this problem when I got up to switch on my machine this morning at 03.26. As I was reading Mepher's answers I kept on switching on and off my computer and at the same time unplugging from the wall socket and plugging again. Repeating this process several times all the time and bingo I got the machine back on track. You need to be patient though. good luck. Please give me a feedback to this suggestion.

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Upvote because this is equivalent to "I smacked my computer really hard and then it started working" which also sometimes solves problems. Also creates some problems, but hey smacking the computer usually makes you feel better. – Nathan Adams Oct 17 '12 at 19:11
    
This worked for me this exact morning. Upvote. – Jean-François Gagnon Oct 1 '15 at 21:49
    
Note that 3am is the default time fro Windows update if you have it switched to automatic. And that has a nasty habit of rebooting without asking for permission. Not that this solves your problem, but it probably explains what started it off. – Mawg Jan 31 at 9:03

Is there a USB stick on your computer which you may have forgotten to unmount?

If your answer is no, I'm going to ask you if you have installed any new hardware to your PC lately. This may be the reason of the error. If so, disconnect any new hardware that you have installed, then start the computer and keep pressing F8, then when the boot screen comes up, select Safe Mode. Afterwards, just wait for it to load up and then run System Restore.

Waiting for your feedback.

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Hmm, thanks for the quick reply Mehper. No, I didnt have a USB stick or anything else that was plugged on the system. I only had a USB cable attached to the computer with nothing else attached to it on the other end. Also no hardware was installed within the last few months. Is there anything else I should try? – Emon Sep 27 '10 at 14:42
    
Have you tried to open it in Safe Mode? – Mehper C. Palavuzlar Sep 27 '10 at 14:44
    
I will give it a shot later today and let you guys know how it went. Thanks for all the help. – Emon Sep 27 '10 at 15:33
    
Mehper, i cant event get to the screen F8 brings. I end up with the same message "Reboot and Select proper boot device or Insert boot media in selected boot device". – Emon Sep 27 '10 at 16:53

Have you double-checked that your computer is booting to your hard drive and not some other device? It's possible your bios decided to try booting to something else after a power failure. To do so, just pick your boot device (it varies by computer manufacturer; usually mashing the F-keys along with the Del key during boot will hit it). Then, pick to boot from your hard drive.

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I solved it by disconnecting my slave drive (2nd drive) and unplugging my main drive. Then I unplugged my power cord for about 15 minutes.

After, I reconnected the hard drive's power and data, then my power cord and turn the computer back on and it booted up back to normal. After that I turned off the computer and reconnected the slave drive.

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A power glitch during the night might have nixed your Windows installation.

If you can't boot in Safe mode to restore the system, you will have to do a repair installation.
See this: How to Perform a Startup Repair in Windows 7.

If this was the problem, and your neighborhood prone to power outages, I would suggest using power protection such as surge suppression or UPS.

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That is the only thing I can think of. It was raining all night yesterday and I am pretty sure there were some kind of power outage took place. Thanks for the quick reply. – Emon Sep 27 '10 at 14:47
    
Harry, I am trying to follow the URL you sent me but I can't get the machine to boot from the CD. Is there any other I can boot from the CD? – Emon Sep 27 '10 at 16:55

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