Thanks! The thing I'm really confused and frustrated

about is that this desktop is very new, I just bought it like four months ago. It's a 4G, dual core Dell. :((

The problem is that whenever I open some new website, even just Yahoo or Google, it took an hour just to load the page, it's very slow. I tried to install the "security guard 360"(I'm sorry that this is in English, my compnay's computers don't have a Chinese output.) mentioned in FLYWXC's post below to clean it up, but my computer was too slow to run it successfully.

Thanks again for your help!