Do you have a router in this mix?
If you have a router, you should be obtaining a IP from the Router, your router should be getting it's IP from your ISP. In which case, your cable is probably bad.
If you don't have a router, there is a good chance your cable may be damaged. Try replacing the cable and trying again.
There is also a somewhat recent virus, within the last 2-3 months, that causes your network connections to stop working.
First, I would replace the cable and test that. Also, make sure you're set to DHCP, which is defaulted generally in Windows, unless you changed it at some point.