Frequent Interruptions in network and problems in watching video streaming

I have Vista home premium and being a new user I am facing a lot of issues.

1) My internet keeps on disconnecting (will rather call it an interruption as I don't need to manually reconnect). I don't have problems in browsing but this interruption (for some seconds) generally disconnects me from any server I am connected to. For Eg. Texas holdem poker on Facebook / Bridge base online / Hamachi ..etc etc..I am having problems playing any game online (.. I tried a laptop having XP and it worked fine so I am quite sure this is not a network problem.

2) I am unable to watch online streaming which is played on wmp. I have installed the add-on (firefox) for it but then also it isn't able to play it. The internet explorer just crashes when I tried to play it on it. I can watch Youtube/ Metacafe videos.

3) Another issue is the loading of Java applet. I have installed the latest Sun java JRE 1.6.0_07.

Someone please help a newbie..

I am having this same problem with my new HP Vista laptop and my school's wireless network. My old Dell XP laptop works fine on the school's network, and my new laptop works fine back at home.