3 days ago I tried to connect the Laptop with my cable and there were no problems..
Ok I thought this was the problem. What type of Network card is installed? Does your status icon shows that you are connected?
1. Run the Network troubleshooter for your Network card for your Desktop.
2. In your Control Panel, Network Connections, Right-click Network Card/Properties/General Tab and highlight TCP/IP click Properties. Are Obtain IP address and DNS server dotted? Check Also Alternate configuration tab if
Automatic Private Address is default.
3. Also for your IE8 Browser. Go to Tools/Internet options/Connections/LAN settings, is automatically detect settings in default?
4. On your Device Manager, check the status of your Network card if it states that it is working properly.
5. You could also try opening browser(IE8) without add-ons. Right-click IE8 icon on desktop and choose Start without add-ons.