Google and yahoo "unable to connect"

Hello. I got my Macbook pro two weeks ago. So far i have had nothing but trouble. I had it for about a week before my printer came from apple. When i installed the divers everything ran really slow and firefox and safari would crash when i opened them. I called apple and eventually brought it to the apple store. In the end I had to do a complete reformat of the Macbook.

I have had it for a week since then and this morning when I tried to look at gmail it said "unable to connect". I then tried to google the problem and that also was "unable to connect". I then tried yahoo and had the same results. i restarted the computer twice and still had the problem.

I first assumed that it was an internet or router problem. I unplugged my linksys WRT54G router and let it restart and tried my macbook. Still unable to connect. I then plugged the cable into the macbook and still could not access the sites.

I tried to go to google and yahoo on my parents iMac (plugged into the wall) and my old vaio (wireless) and they work fine on those.

What should I do?

I should note that iChat can not connect to AIM.

Also, the mac book can connect to some sites (I am using it now) it just can't connect to google or yahoo as far as i can tell.