Stop: c000021a fatal system error bluescreen - After AVAST updating:

[gennnacianca]

Dear friends,

Yesterday I noticed that AVAST free had to be updated and it did not happen automatically.
So I decided to manually update AVAST (in the past the forced update had not worked, but yesterday yes...in three steps).

Afterwards, I was requested to shutdown and reboot the operating system (Windows XP Service Pack 1).

Unfortunately, since then the system continues to get stucked with blue screen and reboot every time:

This is the error message I got, after every reboot:
STOP: c000021a {Fatal System Error} The Windows Logon Process System process
terminated unexpectedly with a status of 0x00000080 (0x00000000 0x00000000).
No way to start windows, also in not full mode.

I tried to repair c: with chkdsk c: /r.  No result. :'(

I am quite sure this was caused by AVAST update, which modified some dll of the operating system.

Do you have any ideas to repair it or do I have to reinstall all (hope not)?

Thank you very much for your support.

[SafeSurf]

I think you should start by updating your OS to SP3.  Why are you using obsolete and unsupported SP1?  This could be part of your problem.

[gennnacianca]

Thank you for the prompt reply.

I did not do it because of the risk of some conflicts with older applications.
In fact, AVAST is one of the few antivirus which still accepts SP1.
This could be the event which will make me update everything.

Is there any other suggestion to avoid it?
Thanks.

[SafeSurf]

What version and product of Avast are you using?  Were you doing anything just prior to the crash?

[Asyn]

In fact, AVAST is one of the few antivirus which still accepts SP1.

Not anymore, it needs at least SP2.
But better update to SP3, as it's the only version still supported by MS.
asyn

[gennnacianca]

For Safesurf: is there any way to retrieve the avast current version from dos interface commands? This is my only way to access files currently.

Thank you.

[YoKenny]

Please read:
What are the supported operating systems for avast! 5.x?
http://support.avast.com/index.php?_m=knowledgebase&_a=viewarticle&kbarticleid=455&nav=0,56,175#idt_01

This applies to avast! V6 as well.

This is from Microsoft:
Support for Windows XP Service Pack 2 ends on July 13, 2010
http://support.microsoft.com/gp/lifean31

[bobo1]

Hi
Can you access safe mode by hitting F8 as the computer is booting? & or go in last known configuration and restore from there?. to a good restore point when the computer worked. You need to be on SP3 as viruses will get in on sp1