Can't boot after xp sp2 install

This is a long story so please bear with me,

I can't boot anymore after I installed sp2. I have a home built
athlon64 machine w/ xp Pro. I can't boot into safe mode or nothing. The
machine freezes after trying to load "Mup.sys." and dies with the
error:

STOP C000021A (Fatal System Error)
The session manager initialization system process terminated
unexpectedly with a status of 0xC000026C (0x00000000, 0x00000000). The
system has been shut down.

I've tried renaming Mup.sys and it fails on the driver before that
(vmodem.sys). I don't know what the driver would be after Mup.sys but
commonly (I think) it is agp440.sys which I renamed to no avail. Based
on my research I don't think it had anything to do with Mup.sys or a
driver. In the microsoft KB there is info on STOP C000021A but the
status is not 0xC000026C.

I have not found a solution and I liked the idea of uninstalling SP2
through the recovery console, as per the MS KB. I get there but there
is no $NtServicePackUninstall$ directory!! (I wrote the background at
the end of the post which points out that the machine thought SP2 was
installed succesfully). My question right now is how can that be????
There are many $NtUnistallKBxxxxxx directories with the date stamp of
the night of SP2 installation but no $NtServicePackUninstall$.

Any suggestions on why this is and how can I get rid of whatever
happened (e.g. spuninst.exe each of the hotfixes???)

I'm trying to do everything short of a repair install so any ideas are
appreciated.

The Background:

Initially I installed sp2 through automatic updates. At the end it
complained that the installation failed and it had to uninstall the SP
(that "items ... manifest ... verification ... failed ..." crap). So it
uninstalled and reported that "Windows may not work properly."

I got lucky and windows booted and seemed to work fine. I researched
this and found many recomendations to avoid the automatic updater and
downlaod the full (272meg) SP2 file and install from that. Stupid me
(slap myself), insisting on installing sp2, went ahead and did that
(download + install). It said that the installation was comleted
successfully. Now I can't boot at all anymore (safe mode, vga mode,
last known good mode, whatever.)

I have tried removing both cdrom drives, and my crappy (not MS
certified) modem. I don't have integrated video so I can't remove the
NVIDIA video card. I'll try removing the sound card tonight.

Enough rambling from me and thanks for your time.

I realize that your message was dated June but I am having the exact same
problem and hope that maybe you can help, that is, if you ever got your
problem solved. I haven't been able to get past mup.sys either and cannot
boot safe mode, or any other F8 option after uninstalling SP 2 through
control panel. What worked for you? I'm running a Sony VAIO PC with XP Home
Edition and unfortunately my XP is bundled in the recovery disks that Sony
sold with the computer. I also don't get the opportunity to view the
particular Stop error, my system just goes into a continuous cycle of trying
to reboot. Thanks for any help you might have. .

"Hass" wrote:

This is a long story so please bear with me,

I can't boot anymore after I installed sp2. I have a home built
athlon64 machine w/ xp Pro. I can't boot into safe mode or nothing. The
machine freezes after trying to load "Mup.sys." and dies with the
error:

STOP C000021A (Fatal System Error)
The session manager initialization system process terminated
unexpectedly with a status of 0xC000026C (0x00000000, 0x00000000). The
system has been shut down.

I've tried renaming Mup.sys and it fails on the driver before that
(vmodem.sys). I don't know what the driver would be after Mup.sys but
commonly (I think) it is agp440.sys which I renamed to no avail. Based
on my research I don't think it had anything to do with Mup.sys or a
driver. In the microsoft KB there is info on STOP C000021A but the
status is not 0xC000026C.

I have not found a solution and I liked the idea of uninstalling SP2
through the recovery console, as per the MS KB. I get there but there
is no $NtServicePackUninstall$ directory!! (I wrote the background at
the end of the post which points out that the machine thought SP2 was
installed succesfully). My question right now is how can that be????
There are many $NtUnistallKBxxxxxx directories with the date stamp of
the night of SP2 installation but no $NtServicePackUninstall$.

Any suggestions on why this is and how can I get rid of whatever
happened (e.g. spuninst.exe each of the hotfixes???)

I'm trying to do everything short of a repair install so any ideas are
appreciated.

The Background:

Initially I installed sp2 through automatic updates. At the end it
complained that the installation failed and it had to uninstall the SP
(that "items ... manifest ... verification ... failed ..." crap). So it
uninstalled and reported that "Windows may not work properly."

I got lucky and windows booted and seemed to work fine. I researched
this and found many recomendations to avoid the automatic updater and
downlaod the full (272meg) SP2 file and install from that. Stupid me
(slap myself), insisting on installing sp2, went ahead and did that
(download + install). It said that the installation was comleted
successfully. Now I can't boot at all anymore (safe mode, vga mode,
last known good mode, whatever.)

I have tried removing both cdrom drives, and my crappy (not MS
certified) modem. I don't have integrated video so I can't remove the
NVIDIA video card. I'll try removing the sound card tonight.

Enough rambling from me and thanks for your time.

Howdy:

Found the following.. suggest you give it a try..

The newest Critical Patches can be the reason for the error, please
uninstall KB893066, KB890923, KB890859 and KB893086

----------------------------------------
Please follow the procedure suggested by microsoft to solve BSOD
problem from the latest windows update.

1. Insert the Windows XP startup disk in your floppy disk drive or
insert
the Windows XP CD in the CD drive or in the DVD drive, and then restart
your computer.

Note When you receive the following message, press a key to start your

computer from the Windows XP CD:
Press any key to boot from CD

Note Your computer must be configured to start from the CD drive or the
DVD drive.
For more information about how to configure your computer to start from
the CD drive or the DVD drive, see the documentation that came with your
computer or contact the computer manufacturer.

2. When you receive the Welcome to Setup message, press R to start the
Recovery Console.
Note Multiple options will appear on the screen.

3. Select the Windows XP installation in question.
Note You must select a number before you press ENTER, or the computer
will restart. Typically, only the 1:
C:\Windows selection is available.

4. If you are prompted to type an administrator password, do so. If you
do not know the administrator password, press ENTER. (Typically, the
password is blank.)

Note You will not be able to continue if you do not have the
administrator password.

5. At the command prompt, type cd $ntuninstallKB.........HERE THE
NUMBER OF THE PATCH.....$\spuninst, and then press ENTER.

Note After you complete this step, you cannot stop the removal
process.

6. At the command prompt, type batch spuninst.txt, and then press
ENTER.

7. After the Ptach is removed, type exit, and then press ENTER oo
Uninstall the Next

please uninstall
KB893066
KB890923

KB890859
KB893086