Can't connect to internet after power failure.

I would suggest unplugging your modem, your router and shutting down all devices. Power up the modem, give it a few minutes. Plug in the router, give it a minute, then power up your PC.

If it still doesn't work. Go into your router, and find the tab that has the routers IP information (mine is the status tab along the top); see that your router is getting an IP from your ISP. It could be that your ISP lost power as well and their servers are still down (but I'm not actually sure if that happens).

You can try getting a new DNS server if you can still connect to some things (like steam friends) but URLs are failing; Google offers a public DNS you can use.

If reinstalling the chipset drivers and LAN drivers doesn't fix it, then there is the possibility that your motherboard took some damage during the power outage.

PC is running fine. I can see the router... so both mb and network card are OK...
Here's a ipconfig / all result


Host Name . . . . . . . . . . . . : my-PC
Primary Dns Suffix . . . . . . . .:
Node Type . . . . . . . . . . . . : Hybrid
IP Routing Enabled . . . . . . . .: No
WINS Proxy Enabled . . . . . . . .: No

Ethernet adapter Local Area Connection:

Connection-specific DNS Suffix:
Description . . . . . . . . . . . : Realtek PCIe GBE Family Controller
Physical Address . . . . . . . . .: F8-0F-41-11-ED-B8
DHCP Enabled . . . . . . . . . . .: Yes
Autoconfiguration Enabled . . . . : Yes
IPv6 address . . . . . . . . . . : 2001:c90:e99 :50c2 :2549 :7172 :6e82 :c983(Preferred)
Temporary IPu6 flddress . . . . . : 2001 :c90:e99 :50c2 :2418 :if ea:22ce :7620(Preferred)
Link-local IPv6 flddress . . . . .: fe80::2549:7172:6e82:c973%11(Preferred)
IPv4 flddress . . . . . . . . . . : 192 .168 .1.2(Preferred)
Subnet Mask . . . . . . . . . . . : 255.255.255.0
Lease Obtained . . . . . . . . . .: Thursday, April 19, 2012 4:14:12 PM
Lease Expires . . . . . . . . . : Friday, April 20, 2012 4:14:11 AM
Default Gateway . . . . . . . . . : fe80::21a:30ff:fe55:301a%ll
0.0.0.0
192.168.1.1

DHCP Server . . . . . . . . . . . : 192.168.1.1
DNS Servers . . . . . . . . . . . : 192.168.1.1
NetBIOS over Tcpip . . . . . . . .: Enabled

Tunnel adapter isatap.:
Media State . . . . . . . . . . . : Media disconnected
Connection-specific DNS Suffix . .:
Description : Microsoft ISATAP Adapter
Physical Address . . . . . . . . : 00-00-00-00-00-00-00-E0
DHCP Enabled . . . . . . . . . . : No
Autoconfiguration Enabled . . . . : Yes

Tunnel adapter Teredo Tunneling Pseudo-Interface:

Media State . . . . . . . . . . . : Media disconnected
Connection-specific DNS Suffix :
Description . . . . . . . . . . : Teredo Tunneling Pseudo-Interface
Physical Address . . . . . . . . : 00-00-00-00-00-00-00-E0
DHCP Enabled . . . . . . . . . . : No
Autoconfiguration Enabled . . . . : Yes

Is your modem showing connected to the Internet? If so, does your router show connected to the internet? Your router should also have a diagnostics page that will let you ping other hosts. You might want to try that too in order to make sure the router can resolve addresses and communicate on the Internet.

Change out the phone cable running from the router to the wall socket.

I could finally get connected to the net, hopefully not only temporarily!
What I did was enter the following instruction at the cmd prompt:
netsh int ipv6 reset reset.log

This reset the IPv and apparently solved the problem, hopefully not only temporarily.

Now the default gateway is not 0.0.0.0 any more.

Anyway, thanks a lot for your support.