Laptop Down/Upload Problems HELP!

Recently for christmas, i purchased an Advent 7111 Media Center 2005

It is awesome, however, whenever downloading files from the internet, or while watching videos online like youtube, metacafe, googlevideo and others, it just happens to stop and freeze during the download.

I can still normally use my computer, however the upload process of the video stops, so if there is any help i can get, i would really appreciate it.

BTW, if u need any details of my specs, just ask.

First; Is the machine clean from viruses/trojans AND do you install MS Updates?

Second; is your firewall active?

My machine has Norton Business Edition and another protection, cant remember, and my firewall is on, (not the windows one, the Norton one)
And i dont know what you mean, MS Updates?

Microsoft Update Service here