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Computer not booting, need diagnosis asap

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#1
So I booted my computer today, only to be greeted by a black screen, taunting me with a blinking underscore (_). The computer manages to get through all of the usual BIOS messages just fine, but then hangs at the aforementioned screen. I tried Windows startup repair, which told me that everything was fine on my HDD. I tried resetting my BIOS via removing the lithium battery; no dice. I tried booting with one stick of RAM (of 4); no dice. I'm thinking my CPU is the problem, since it's been acting up lately. Still, I would like the insight of the TPU computer masterminds before I drive over to Fry's and blow like $500 on a new CPU/mobo.

If the CPU is indeed the problem, I'd also like some insight as to what CPU/mobo to replace it with (I would like to play Battlefield 3 on high settings when it comes out, if that helps gague what I'm looking for).
 
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#2
I know this is kinda stupid but did you make sure you don't have any extra bootable media connected (CDs, USB drives, disks, etc.)?

I only say it because the blinking underscore, with an otherwise blank screen, usually indicates that the BIOS is attempting to boot the primary boot device (whatever it may be).
 
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#3
Did you change any hardware recently and what psu are you using ?
 
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#4
I did try booting with as few extra bootable media as possible, to no avail. I also have a Corsair HX 750W PSU, and haven't made any modifications to my computer since June '10.
 
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#5
Sounds like your HD might be dead. Try moving your SATA cables/ports. Could be that also.
 
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#6
Rearranging my SATA/HDD cords didn't alleviate the problem. It might be worth noting that the 'main' BIOS menu shows both my main HDD (WD) and my backup (Seagate), but under 'boot device priority' my main HDD is not an option. Normally this would be pretty conclusive evidence; but prior to today's failure, my backup HDD had been plugged in to SATA1, and would have to be set to'1st boot device' in order for my main C:\ drive to boot (strange, I know). Unplugging the Seagate gives me a completely black screen after the usual BIOS messages, as opposed to the underscore screen. I rearranged the wires to have my main WD plugged into SATA1, which didn't do anything new.

Edit: My BIOS just froze, so I had to reboot. Now absolutely nothing is showing up at all. Plus, it just reset itself when I tried to boot it just now...The plot thickens.....
 
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#7
Have you tried booting without any HDDs plugged-in?
 
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#8
Have you tried booting without any HDDs plugged-in?
Just tried that (mobo managed to load, unlike previously), it just wants me to reboot and select proper boot device.

It might be worth noting that the computer shuts off every time I boot now.
 

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#9
Sounds like it's possibly restarting/freezing due to heat protection? Try reseating the CPU and the cooler.
 
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#10
Sounds like it's possibly restarting/freezing due to heat protection? Try reseating the CPU and the cooler.
Sorry, but how might I go about doing that?
 

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#11
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#12
Ya know it sounds strange but I have had this happen to me before. The only way I could fix it was to reinstall windows.
 
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#13
sounds like it is video related.

If you can hit f8 right after the bios splash screen, it should give you the option to get into safe mode. If you can get there its more then likely driver related.

Try reinstalling your video card drivers.

If you cant get to safe mode.. try a different video card
 
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#14
sounds like it is video related.

If you can hit f8 right after the bios splash screen, it should give you the option to get into safe mode. If you can get there its more then likely driver related.

Try reinstalling your video card drivers.

If you cant get to safe mode.. try a different video card
I don't know if it's just me, but f8 just brings me to the 'select boot device' menu. I was able to get in to the startup repair menu via the Windows 7 disc I have. I don't have an extra video card to test with, unfortunately.
 
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#15
I really doubt this is video card related.. Or cpu related..

Sounds like ur HD shit the bed, your gonna have to reinstall windows on a new HD.
 
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#16
Does it make any difference that all of my C:\ files were in tact when accessing them via a usb dongle (the kind that lets you hook up an internal HDD via USB)? Plus, Windows's startup repair said there weren't any problems.

Excuse my noobiness, just trying to be 100% clear on my situation.
 

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#17
Looks like you've got a competing bootloader. Disable other boot options in BIOS, see if that works.

Edit: this is what happens when I leave my external drive plugged in. real simple fix for me, not so much so for you. and don't worry about being a noob, you're not the only one on here, lol.

If you can't disable other boot options, try and disconnect the backup drive and restarting.
 

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#18
what you say is caused by the CPU, but the CPU may not have gone KAPUT.

try taking the CPU out of the socket and airclean the socket and the CPUs pins,

Then using fresh TIM reapply the cooler, clean the cooler too if needed.


this type of a problem seemed to occur if the HSF was on too tight on my PC
also make sure you didnt bend any CPU pins.


also make sure your RAM sockets are dust-free clean them with air.


also check that the sata cable to your HDD is connected tightly at both ends
and that there isnt any dust there either.
 
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#19
it sounds like a borked windows install to me... dunno why u guys think its hardware.. if anything its the hard drive
 
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#20
it sounds like a borked windows install to me... dunno why u guys think its hardware.. if anything its the hard drive
I agree with ShiBDiB. If anything is bad its the HD. Other then that its a software issue.
 
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#21
I also believe the issue deals with boot order and hard drive issues. I have had this issue before when i was messing with my computer and had to unplug all of my hard drives. If your main hard drive doesn't appear in the boot list then there might be an issue with your SATA cable or socket on the motherboard. You may want to back up your information onto another drive and attempt reformatting the drive or formatting a spare hard drive and seeing if the computer can boot from that spare drive in all the ports you've tested so far with the bad drive. usually the underscore means its trying to access something but having issues. It sees that there is something to boot from but cant seem to boot from the device for some specified reason. All i can say is check the hard drive since that seems to be the issue since you can boot from a CD. Also see if the backup hard drive isnt first in the booty priority since my motherboard gives boot priority and then has an option to select which hard drive to boot from first in line. Hope some of this might help.
 

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#22
I don't think your HD is necessarily bad, and this might not be your problem either, but I've seen viruses lately that corrupt the boot sector and cause that blank screen with the flashing underscore. If you use the Windows disc, get to Repair Your Computer, and then choose the command prompt, you can go to your drive letter (assuming C:) and then run:
fixboot C:
followed by
fixmbr C:
And that will attempt to repair it. It doesn't always work, but it's worth a shot. It usually only takes a few minutes for each process.
 
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#23
Does it make any difference that all of my C:\ files were in tact when accessing them via a usb dongle (the kind that lets you hook up an internal HDD via USB)? Plus, Windows's startup repair said there weren't any problems.

Excuse my noobiness, just trying to be 100% clear on my situation.
+1 to a toasty bootloader/Windows install. Sounds like the HD got whacked.

What version of Windows? I'm assuming 7... If its XP then everything below doesn't do anything.


Instead of doing a repair, you should be able to launch the CMD prompt from that Windows 7 DVD (If I recall). Launch that and run the following:

Chkdsk /f C:\ see if anything picks up in that scan.

If it finds errors, reboot and see if you can boot into Windows.

If it produces the same error your BCD could be whacked (Windows Boot Loader)

Perform the following steps below..If you are not comfortable with this then I wouldn't continue.

bootrec.exe /fixmbr
D:\boot\bootsect.exe /nt60 all /force

del C:\boot\bcd
bootrec.exe /rebuildbcd

shutdown -r -t 0

Where D:\ is place your CD Drive letter.

Beware that this MAY not work. Depending on when the 7 CD came out, I don't think ALL copies had boot folder on it, just earlier releases.

And If all else fails..theres more you can do..but its almost easier to install Windows 7.
 
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#25