Windows XP: C000021a {Fatal System Error} with a status of 0XC000135

C000021a {Fatal System Error} with a status of 0XC000135

Hello everyone,

Yesterday, after a sudden reboot, I got the blue screen with the following error message:
"Stop: C000021a {Fatal System Error} The Windows Logon Process system terminated unexpectedly with a status of 0XC000135 (0x00000000 0x00000000). The system has been shut down."

System: Sony Vaio VGN-SZ160P laptop with Windows XP Pro installed on it (no new part except a 1Gb of additional RAM has been added).
(Note: My computer did not come with the recovery disks, and apparently Sony does not carry the disks anymore. since it's more than two years old).

What happened before I got the message:
I turned on the computer and everything went well after a cold reboot. Windows update notification popped up informing me that new updates are being installed on the system. After the installation was complete (no prompt on "restart is required"), I ran a full diagnostic through Symentac (deleting temp files, runnig a virus scan, and defragmenting the HDD). Then, I decided to clean up some space and get rid of some of the programs I did not need (among those, I deleted Adobe Reader 7.0.5 with update [since I had adobe reader professional 7.1 installed], AnyDVD, Safari browser, Google Toolbar for IE Explorer, and couple of other 3rd party programs). However, in the middle of these removals, my computer suddenly rebooted (I assume one of the programs required a booting to complete the uninstalling process)..Next thing I know, I am stock with the BSOD.

I tried to access the operating system under the safe mode, however NONE of the options work. And, as I mentioned earlier, I don't have a recovery disk set to be able to get the recovery console or perform an in-place OS installation. I have been researching on the topic for a few hours now, and every working solution so far has either been with accessibility to command prompt under the safe mode, or an in-place OS installation. Some one else had suggested to access the system via Knoppix.

I have many important files on this computer, so, naturally, I would like to keep a clean install as my last resort.
I am really desperate to get my system back up and running. Any help or suggestion is truly appreciated.

Thanks.