Vista - Problems with downloading and watching Youtube videos

Hi, Sorry if this has been answered previously.

Recently bought a Packard Bell Easy Note with HOme PRemium installed. I have set up the internet which is working correctly. When I try and download files or watch videos on youtube, it always gets part of the way through (about a third) and then just freezes. It will allow me to download very small files but I have tried to update itunes, real player and it will not complete the download. Its the same with Youtube too... can only watch about a quarter of videos.

The internet works perferctly fine on the wireless.. but not downloading. However it will download the security updates from Windows, which are now up to date and the problem has not been fixed.

I've tried lowering my security settings and have uninstalled Norton 360 that came on the PC.

I previoulsy had XP and that worked fine on this internet.

Can anyone help or suggest anything? I just can't figure it out!