I can't be sure why you have the problems with the online scan and download Spybot, but I really have to suspect an active infection. Try downloading Spybot on another computer, then go to Safer-Networking and download the detection updates file. Copy the installer and the update file to a pendrive, burn a CD, or whatever, then install Spybot on your computer, and after it is installed, run the update and scan. If you haven't been able to download a trial of NOD32, you should be able to install it the same way.