Major XP problems w/booting & blaster virus

[jgtyler3000]

Thanks very much for everyones attention to this. I am brand new to this forum so I hope I am doing this right.
I am posting this for help with a friends computer since she has an apparent MAJOR problem and can not boot up or access anything.
This started this morning for her. She recently switched from a cable modem to DSL with SBC/Yahoo. The install of the DSL program went fine. One of the options during the setup was to select different programs from SBC/Yahoo. One of them is an anti-virus software program which she selected. She installed the program and ran it. Please note that everything up to this point seemed to be ok. Anyway, after running the anti-virus program, it found several apparent viruses & bugs. She used the cleanup/repair feature within the program and after it was all done, it prompted her to reboot.
This is when everything began to go wrong. As the computer rebooted, it took her through the Gateway screen and through the Windows XP screen and then to a blue screen which stated a fatal error or exception occured. She then called DSL tech support and after several minutes or prompts, she got to a live person who told her she had the dredded "blue screen of death"! It would stay on the blue screen for several seconds and then reboot to do it all over again (a viscious cycle I might add!!!). It kept doing this over and over.
Naturally she freaked! I got it in the past and I freaked too!
The tech support rep told her it is a Blaster virus which downloaded with of all things, the SBC/Yahoo DSL anti-virus software!!!
Tech support tried to get her to start up in Safe Mode but that appears to be a problem as well. She is asked for a log on to windows password which she enters and for a brief moment her desktop background flashes then it logs off and returns to the log on to windows screen. She no longer gets the blue screen of death.
I hope I am explaining all this well enough for anyone to help.
An additional problem is that she does not have the Windows XP disks that came with the computer.
I have been researching all this on your site and everything I have found points to the need for the Windows XP disks and/or the ability to get into safe mode from which she could hopefully load the blaster repair tool (which I could download for her).
All else that I can tell you is that she has a Gateway computer with a pentium III 700 mhz processor. I don't know the ram or other things.
HELP US PLEASE!!!

Thanks...Pat

[sp_100]

Please try the Last Known Good Configuration.

If it doesn't help, try the System Restore.

If no go, please post the exact error message.

[jgtyler3000]

Nothing works when she tries to get to the last known configuration and when she tries safe mode with command prompt, it does the same thing as without the command prompt. She is totally stuck right now.
Any other suggestions?

Thanks...Pat

[sp_100]

Please post the exact error message. Thank You.

[jgtyler3000]

When she was getting the blue screen of death with the error message, it would be displayed for several seconds before it would go away and then the reboot process would start over again. If she can get the blue screen to come back again, is there a way to freeze it so she can write down the exact error message?

Thanks...Pat

[sp_100]

You could try the Recovery Console, but it requires a Windows XP CD.

Contact Gateway, they may have some nondestructive restore option …

And check back … maybe someone else will have better solutions.

[jgtyler3000]

Thanks!. Do you know if any Windows XP CD will work? Can I use a Windows XP CD from another computer?
I have a Windows XP upgrade CD (I upgraded from ME). Do you think the upgrade version would have the recovery console?

Thanks for your assistance...Pat

[jgtyler3000]

Here is the beginning of the error message that she is able to write down:

Stop:C000021a FATAL SYSTEM ERROR

Does anything think this helps to unravel the mystery???

Thanks...Pat

[sasarchiver]

I found this article, hope it helps...I think ud be quicker re-installing windows, unless u want to recover some stuff on the HDD.

Stop 0xC000021A messages occur in a user-mode process and the most common causes are third-party applications. If the error occurred after installing a new or updated device driver, system service, or third-party application, you need to remove, disable, or roll back the driver, or uninstall the new software. Contact the software manufacturer about a possible update.
System file mismatch caused by partially restoring the system from backup media might cause this error (some backup programs do not restore files that they determine are in use). Always use backup software that is Windows XP Professional compatible.
If SYSTEM account permissions were altered, follow the procedures below to regain access to the boot partition:
Perform a parallel Windows XP Professional installation onto a separate partition or drive. Do not use the original drive and folder names because the new Windows XP Professional installation overwrites previous settings. Complete the second installation.
In the Run dialog box, in the Open box, type: c:
Right-click the original Windows XP Professional systemroot folder, and then click Properties.
Click the Security tab, and then grant the local SECURITY account full control of the systemroot folder and its subfolders.
Restart the system, and then select the original Windows XP Professional installation from the startup menu