Yes, this is an old problem that I've read about many times on this site and several others and tried just about every fix/suggestion I've seen. Nothing has kept it from happening every couple of days. I'm NOT an IT pro, far from it, but have learned an awful lot in the last 3 years. I even put a new HDD in my desktop recently, something I would have thought 3 years ago that I'd have as much chance of accomplishing as a liver transplant.
When I call my ISP tech line after losing internet connection they usually walk me through to the point that I end up on black cmd screen (as administrator) and when I enter IPCONFIG it shows - Autoconfiguration IPv4 address that starts with 169 - and the tech says, "that is it looking at itself" and after going through IPCONFIG/RELEASE and then IPCONFIG/RENEW - I get a valid address like 126.96.36.199 and everything is fine for a day or two until it happens all over again.
It seems as though this problem must be unique to Windows 7 since while my desktop was down and installing a new HDD I had borrowed an old laptop from a friend that had Windows Vista and I had no problems of this kind for a full month. I also wonder if this has something to do with the "Autoconfiguaration" Any thoughts on this?