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Some days ago, I was using one online TV S/W, when it caused my PC to not respond, after waiting a bit more, I decided to reboot manually.

It failed to reboot and BSOD happened, it said

stop:c000021a unknow hard error

Then I had to reboot by force.

Then I formatted the whole disk and decided to reinstall my OS. After the process finished, I could enter the OS, but after installing the drivers, such as sound card, graphics card etc. I couldn't enter the OS any more.

Well, I just continued to reinstall again. I thought the process would be ok, installed drivers and during the reboot, BSOD, again. It said

physical memory dump complete

PS: The reinstallation of XP and the relevant drivers was working normally before and I can reinstall the OS successfully with the same method above. I checked the HDD, it is working.

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Wow that question is VERY hard to read! Imho a hardware failure somewhere. – Jarco Jun 14 '11 at 9:28
I tried to clean it up. Yep, definitely sounds like a hardware error. Maybe try to install every driver one by one and see which fails. – slhck Jun 14 '11 at 10:05
Many thanx! I had done it. – jesseyoung Jul 7 '11 at 5:23

First of all, test the system memory using a low level memory test utility such as:

You will need to download a CD image, burn it to a CD and boot your computer from the CD.

The test is fully automatic.

Once you will be sure that the system memory is OK, connect the hard disk to another computer and check disk S.M.A.R.T. attributes.

SMART attributes show disk hardware status, amounts of errors, etc.

There are many free programs capable of showing SMART attributes, I am personally using SpeedFan.

If the disk is OK, try to install drivers one by one with reboots and check which driver causes the problem.

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Hi, i have tried the tool and no error found. Finally it works well.Thank you so much! – jesseyoung Jul 7 '11 at 5:21

If you are trying to install Windows XP from scratch on the laptop, please BE SURE that you put the hard drive in "Compatibility" mode in the BIOS, which was defaulted to "AHCI" (Compatibility is also known as IDE).

Otherwise, you will experience "blue screen" issues. To change that setting, you need to do the following:

  1. Press F2 when booting up the computer
  2. Select Config, then Serial ATA (SATA)
  3. Change controller option to Compatibility / IDE
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Disconnect any non essential hardware, extra hard drives, xtra optical drives, add in cards (unless one is needed for video), etc, then try to install XP.

Note the position of add in cards and cables to xtra drives and return them one at a time to the same position, try to boot XP each time you add one, if you get the bsod again, you have found the problem hardware.

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Hi when i turn on the PC and it informed me to continue installing the OS, then i plug in the CD and wait the installaiton complete.After that, i reboot and can enter the desktop, then i installed the drivers, surprising! It works well.Thank you for your advice! – jesseyoung Jul 7 '11 at 5:20

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