My HP computer keeps disconnecting from the internet?

[Sleepy Sarah]

It keeps disconnecting and/or saying it can't find any available networks, even though I'm sitting places where I know there are plenty of available options. It will stay online for a while, and then all of a sudden, it will insist there are no connections available. At school, for instance, there are four or five networks, and everyone aound me are connected, but my computer will suddenly refuse to go online for a while, before suddenly reconnecting.

What could be causing this? The computer is less than a year old.

[Sourav]

I think this is happening for port problem or Operating System problem.