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Hi<br />
<br />
you could try to do a repair installation of windows .<br />
Instructions here : <a href="http://pcsupport.about.com/od/operatingsystems/ss/instxprepair1.htm" rel="ugc">http://pcsupport.about.com/od/operatingsystems/ss/instxprepair1.htm</a><br />
Also be sure to check stuff like your memory, and system temperature.<br />

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Hi

you could try to do a repair installation of windows .
Instructions here : http://pcsupport.about.com/od/operatingsystems/ss/instxprepair1.htm [http://pcsupport.about.com/od/operatingsystems/ss/instxprepair1.htm]
Also be sure to check stuff like your memory, and system temperature.


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Please have a look at this and also an earlier post in EE on the same<br />
<a href="http://support.microsoft.com/kb/316503" rel="ugc nofollow">http://support.microsoft.com/kb/316503</a><br />
<a href="https://www.experts-exchange.com/questions/20790028/message-on-bootup-stop-c000021a-fatal-system-error-the-windows-logon-process-system-process-terminated-unexpectedly.html" rel="ugc">https://www.experts-exchange.com/questions/20790028/message-on-bootup-stop-c000021a-fatal-system-error-the-windows-logon-process-system-process-terminated-unexpectedly.html</a>&nbsp;<br />

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Please have a look at this and also an earlier post in EE on the same
http://support.microsoft.com/kb/316503 [http://support.microsoft.com/kb/316503]
https://www.experts-exchange.com/questions/20790028/message-on-bootup-stop-c000021a-fatal-system-error-the-windows-logon-process-system-process-terminated-unexpectedly.html [https://www.experts-exchange.com/questions/20790028/message-on-bootup-stop-c000021a-fatal-system-error-the-windows-logon-process-system-process-terminated-unexpectedly.html] 


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System will not boot up even into any of the safe modes. i want to avoid having to reinstall windows xp onto the system. system comes up with windows xp then blue screens and reboots. I have tried running a check disk with no change superantispyware with no change.
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System will not boot up even into any of the safe modes. i want to avoid having to reinstall windows xp onto the system. system comes up with windows xp then blue screens and reboots. I have tried running a check disk with no change superantispyware with no change.

error code c000021a- system failling to boot

Microsoft Windows XP is the sixth release of the NT series of operating systems, and was the first to be marketed in a variety of editions: XP Home and XP Professional, designed for business and power users. The advanced features in XP Professional are generally disabled in Home Edition, but are there and can be activated. There were two 64-bit editions, an embedded edition and a tablet edition.