also a newby so these may be slightly idiotic suggestions/ideas but here goes.
Use your machines disc cleanup/defrag OFTEN. you'd be amazed at how much CRAP accumulates just from bare minimal web surfing. Dics cleanup removes most of this.
Use a browser that has as much embedded protection as possible- Firefox, Opera are my 2 best reccomendations- i'd avoid IE as much as possible and netscape isn't as bad but nowehre near as good as FF
run teatimer all the time - yes it sucks a LOT of cpu power but its well worth it.
anytime your machine does something that you find even remotely weird, send an email to spybot team and ask about it. Odds are you will get a better answer than just assuming you goofed.
use your SySTEM Restore Point often. this can save you from having to do an entire disc/hard drive reformat - and yes I goofed once and had to do a reformat cause I wasnt using my restore point system as I should have.
Make sure your machines factory supplied firewall settings are up and current. The factory supplied firewall protection isnt the best, but it is your FIRST line of protection - make sure you always have it on and updated.
Lastly, keep your modem/inetrnet cable close at hand. if all else fails(and it sometimes does) unplug from the net, isolating your machine.
hope this helps