Honestly, it could be any one of a number of things. First of all, did you update the definitions for spybot when you ran it? Both spybot and adaware rely on definitions (like virus scan software) that must be updated regularly. Even if you go download the newest version of spybot and/or adaware to install, their defs will not be updated. Update spybot and run again. There should be some kind of an online update button or icon. I'd do the same for adaware, I don't think it should be a problem to have them both installed at the same time.
If that doesn't work, I'd check to see if the web browser is the problem. Try and install Mozilla's firefox browser http://ftp.mozilla.org/pub/mozilla.o...xSetup-0.8.exe
It's very light weight and should load pages fairly quickly. See if you still have the same slowness browsing with Firefox. If firefox is able to render pages quickly, then you can probably isolate the problem to Internet Explorer (which I assume is what you're using). If firefox also loads pages slowly, then we can check other things (disk free space, virus missed by Norton, network issues, etc...).
Keep us posted.