Toshiba - Satellite A75-S1253 STOP: c000021a {Fatal System Error} The Windows Logon Process system process terminated unexpectedly with a status of 0xc0000034 (0x00000000 0x0000000) The system has been shutdown.

Try booting to Safe Mode, or otherwise getting to System Restore where you can back up to a restore point created before the update. Here's a Google search for causes of that error message:

https://www.google.com/search?q=0xc0000135&ie=utf-8&oe=utf-8&client=firefox-b-1-ab

It appears that your Windows Registry is corrupted. You can try to use a Registry repair utility like CCleane to fix it. If that doesn't work you will have to reload Windows OS (Operating System). For more info no this error code Google "c000021a".

hello sir

this problem belong to ram or hdd if have some bad sector... check on by one Thanks

Here is a link to where you can create your own XP recovery CD
http://www.diskinternals.com/boot-cd/
Hope it helps

this is hdd problem u need to repalce... Thanks

reinstall your OS from disc this should cure this problem

There are lots of possibilities like faulty ram or may be virus in the system or may be the windows file is corrupt try to repair the windows installation. or take the backup of system and the format the system

damaged OS windows or most commom hard drive failer..

usually blue screen comes from unstable video memory or windows system or HD.
you may try
1) reinstall windows
2) change another HD to install windows
3) change new ram memory or change memories slot between one and another
if not fixed, to be sure your video memory damage which is insualted on board(separated with RAM), only the hardware repair can be fixed.

plz give your motherboard make and model and the operating version