Stealth Virus preventing Windows update completely undetectable.

Annoying experience beyond words.
Both Pc´s on my network have been infected with this whatever it is.
It started with me getting an alert from my real time AV scan service, a Symantec corporate edition which told me it had detected some SD.Bot virus and removed it. Since i noticed that windows was giving me an alert that automatic updates had been turned off. When trying to turn it back on i recieve an error message and i can also see that the "automatic updates" service is completely gone from the list of services available on the PC. Furthermore i cannot manually run windows updates from the website.
I have scanned with the following tools both in normal and safe mode all of which are unable to detect anything besides my VNC server as a vulnerability.

-Hijackthis - Nothing unusual to see
-Symantec corporate AV client
-Kaspersky AV client
-SUPERAntiSpyware
-Trend micro housecall Online scanner - Runs very strange like something is blocking it.
-Kaspersky online scanner
-Windows malicious software removal tool
-Windows defender

Oh, win xp sp3 by the way.

Furthermore i have tried to boot up the pc in Linux (ubuntu) and tried to run a scan with Clam av but for some reason i am unable to mount the drive within Linux so i cannot scan it.

Any ideas / help would be much appreciated.

Thanks.

 

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Please follow the instructions in the below link and attach the requested logs when you finish these instructions.

• READ & RUN ME FIRST. Malware Removal Guide

• If something does not run, write down the info to explain to us later but keep on going.

• Do not assume that because one step does not work that they all will not.

Notes:

1. If you run into problems trying to run theREAD & RUN ME or any of the scans in normal boot mode. You can run steps in safe boot mode but make sure you tell us what you did later when you post logs. See the below if you do not know how to boot in safe mode:
   
   • Starting your computer in Safe mode
2. If you have problems downloading on the problem PC, download the tools on another PC and burn to a CD. Then copy them to the problem PC. You will have to skip getting updates if (and only if) your internet connection does not work. Yes you could use a flash drive too but flash drives are writeable and infections can spread to them.