refuso

Aha, there's your problem.

When you receive an IP address beginning with 169.254.x.x this tells us that you are having problems connecting to the DHCP server. Whenever your computer can not reach the DHCP server, it will give you an alternate local address; prefixed with 169.254.

There are a few reasons why this could happen.
1) Faulty ethernet card
2) The DHCP server you're trying to connect to has run out of IP addresses
3) The DHCP server has assigned IP addresses already, but your computer didn't pick it up.

Just to check your adapter is connected properly, go to command prompt and run: ping 127.0.0.1. If you get a reply, then we know all is well with that. You may also run: ipconfig /all - that will clarify that you aren't seeing a DHCP server or if DHCP is somehow disabled.

Perhaps try reinstalling your network card drivers as well, then open command prompt and type the following two commands:
ipconfig /release
ipconfig /renew