c000021a Fatal System Error

Vir, Windows Defender, the spyware protector and Windows Defender Offline .... are not they two totally different things?

Vir Gnarus said:

Hmm, I guess it is. I always thought it was just a standalone version of Windows Defender. Thanks, Arc.

Clarifying my thoughts to you .... I am behind a BIOS/boot virus in this case, one of the cause is the OPs statement here:

sp33dyk said:

Also, forgot to mention that System Repair screen also takes a lot of time to load; i thought it was the DVD, but USB was also slow.

And is there any chance of my HDD being at fault?

So it is not only the HDD, but the other things are also slow there. As TDSSKiller scans from within windows, I suggested WDO here, which scans out of windows, and scans in total.

If my understanding of the issue is wrong, and you rectify me, I will be really happy; as I always get real time coaching from you, my teacher :)

Can you dismantle the computer and re-seat some stuff like the SATA and power ports, RAM modules, the COMS battery, the GPU etc (apparently no need to remove the CPU, and it may cause problem in re-seating if you dont have thermal paste).

Not too sure, but this might be helpful.

I expected that WDO will work there.

Well, I read your reply; Arc and decided to reboot and reset the BIOS settings. I loaded the Fail Safe settings and guess what? Windows Defender Offline loaded! ..yup I was happy to see something work, cause slow system irritates me like hell.
It started a Quick scan and nothing was detected. I wanted to do a Full Scan but it's 2 AM here and I think i might do that tomorrow.

About the HDD tests, all tests said PASS:
SMART took mere 10 seconds,
Short DST took about 5 mins at first attempt; i wasn't sure about exact time, so i did it again and this time it took less then 2 mins,
Short Generic took less than 2 mins.
I will be taking backups in case if something goes wrong, but please let me know the probability of my HDD being bad. :P

And I tried to run the FixIt and got this:


Also, when I rebooted after WDO scan, I was asked something like if i wish to set SATA to AHCI mode or something... please tell me what shall I select. I don't remember what I had selected, but yes I did search a bit before I selected something. xD
Also, there's something ya need to know; the network connection used to go off randomly (but less often) and I was unable to access my router's page too. And when I ran Troubleshooter, it detected some error and said Default Gateway wasn't set and it's now fixed. Lol, I was posting this and I realized that this error still exists. :|

So my question is: was it the BIOS settings? Or there's something still hiding in there? :P

Thank you very much to both of you for instant replies!

EDIT: While WDO didn't work, I downloaded Avast's rootkit tool and let it update it's definitions. Then I started the quick scan and after ~10 minutes while the scan was ON, I got BSOD. This one was having text through the screen, unlike the ones I got after Starting Windows screen.

It must not be the BIOS settings, but something necessarily with the BIOS. In my best assumption, after the BIOS reset, it should work a bit better, at least. And, something else should be playing there, which we are also to find out.

Can you reset the router manually? I gewss there should be a small hole and a pin is to be inserted in it to reset the router. Better you follow the manual, but the process should be something like this.

In my computer, SATA is set to AHCI mode. Probably you can also do it, windows 7 should not face any problem, but XP probably cannot boot at AHCI mode.