Problems with Latitude E4300 and the net connection

​Hello, ​

​I have the Latitude E4300 laptop. I bought it a moth ago, more or less. And I always have had some problems with the net driver or with the windows xp configurations. The main two problems are:​

​1. I can't access to other PCs in my network. I only can see my computer and my shares folder. I have changed everything the computer's name, the workgroup's name (now it is the same in all computers), i have updated the net drivers (all of them), i have updated windows xp, and so on. But, it still doesn't work. ​

​2. And, when I try to access to web pages, I can see them without problems but if the network has a low internet connection and i try to access to many pages (4 or 5) at the same time I have problems because I get a message like "the connection has been restarted" and I have to refresh the web page many times to read it.​

​I have tried in many networks and the problems are always the same. And, in the same computer I have Ubuntu and with that operating system the computer work fine. So it has to be the driver or the windows xp configuration. But I don't know what else I have to change. Could anyone help me?​