Videos won't play - bandwidth prob?

[emma_cnp]

Hi - I looked to see if this had been answered before and I didn't see it, but sorry if I missed it...
I just got a new Macbook (10.5.6, 2.4GHz Intel core, 2 GB memory 1067 MHz DDR3) to replace my retro 2005 ibook. I love it, except that it won't play videos on Hulu or Fancast, or any other website playing longer videos. The videos load, but the play skips and stops every few seconds, making it totally unwatchable. It plays stuff on youtube just fine. I tried a bunch of things, like downloading the latest version of Adobe Flash Player and stuff, but the problem hasn't gone away.
Hulu told me to check my bandwidth, and the online tests told me my download speed (depending on which test) is between 400-500 Kb/s, while my upload speed in in the thousands of Kb/s. I know absolutely nothing about this, but the websites said the numbers are supposed to be closer together - is there something I can do about this? Is this really what's causing my lack of video watching?
I'm also trying to watch something from Netflix and it is taking about 35 years to buffer the 21 minute episode.
I'm on my college's network, but I'm on the same network that I was on my old computer, and that ran these videos just fine.

Any help would be immensely appreciated!
Thanks!

-Emma