Some malware has disactivated my antivirus?

Hello! I hope someone can help me.

Something has disactivated my antivirus (AVG 7.5, Spybot Search and Destroy and Norton AV 2005, as well as Zone Alarm firewall) so that I can't reinstall them. I've also tried to install Bit defender 10 and Avast to try to find that virus or troyan, but I just can't install any. SuperAntispyware, which I also use, detects some threat but the computer reboots with an error before being able to finish the scan. And Ad-aware just detected some low risk tracking cookies I could delete.

I can't start windows on safe mode or connect to the internet (neither the wi-fi nor the router cable directly - windows can't start WZC).

I formatted the laptop last week... so I'm not doing it again :'(

Yesterday I got Norton saying I had a Downloader virus, but it was supposedly deleted.... I guess not.

Please help!!

Some malware has disactivated my antivirus?free adware remover

I think all those antivirus are conflicting with each other. You can only have one AV installed at a time and your AVG 7.5 is gonna conflict with your Norton for sure, not to mention when you brought Avast *and* Bitdefender into the mix... all of your resources are going into family feud here with nothing left to run the computer!

Is that Norton 2005 still active and updating? If it isn't, axe it!