Suddenly no internet access anymore

Internet used to work fine but has always been a pain to set up. This morning I _suddenly_ had no connectivity anymore whats-o-ever, it worked fine yesterday. I've had this problem before (where suddenly the internet is gone) but this time I've been unable so far to find the culprit.

I am running Win7 32bit Ultimate, on an Asus M3N78-VM motherboard (LAN chip Realtek RTL8211C). I have the nVidia nForce network driver (no idea how I got that, can't find updates either). I am also running Hamachi, perhaps this gives trouble?

The problem:
Whenever I changed some settings in the network configuration (the LAN adapter -> configure), then when I press close in the adapter window it more often then not freezes. I have to bring it down with the Task Manager, or restart the computer. Same thing whenever I disable / enable the adapter, it just freezes (I must do a hard reset then!).

This is a frustration for long, and I guess the cause of the internet problems. It can have internet but whenever I need to fix it, like now, I just can't get through. The following post used to work: Possible solution for unidentified network access but doesn't anymore (it always freezes when I set the Network Address).

This is what ipconfig /all gives:

Windows IP Configuration

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

Ethernet adapter Hamachi:

Connection-specific DNS Suffix . :
Description . . . . . . . . . . . : Hamachi Network Interface
Physical Address. . . . . . . . . : 00-23-C3-E7-12-6D
DHCP Enabled. . . . . . . . . . . : Yes
Autoconfiguration Enabled . . . . : Yes
Default Gateway . . . . . . . . . :
NetBIOS over Tcpip. . . . . . . . : Enabled

Ethernet adapter Local Area Connection:

Connection-specific DNS Suffix . :
Description . . . . . . . . . . . : NVIDIA nForce Networking Controller
Physical Address. . . . . . . . . : 34-67-54-57-65-65
DHCP Enabled. . . . . . . . . . . : Yes
Autoconfiguration Enabled . . . . : Yes
Link-local IPv6 Address . . . . . : fe80::d59f:7e23:843f:92c8%13(Preferred)
Autoconfiguration IPv4 Address. . : 169.254.146.200(Preferred)
Subnet Mask . . . . . . . . . . . : 255.255.0.0
Default Gateway . . . . . . . . . :
DHCPv6 IAID . . . . . . . . . . . : 268444181
DHCPv6 Client DUID. . . . . . . . : 00-01-00-01-12-A3-21-36-00-22-15-B4-49-63

DNS Servers . . . . . . . . . . . : 208.67.220.220
208.67.222.222
NetBIOS over Tcpip. . . . . . . . : Enabled

Tunnel adapter isatap.{F68B6DC3-FC63-40EA-AB07-C133FB16B94B}:

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 Local Area Connection* 11:

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

I have a router, on IP 192.168.1.254, a SpeedTouch 5x6. Static IP or DHCP doesn't matter for me, whichever works.
What is weird also, is that the subnet mask is 255.255.0.0, instead of 255.255.255.0, problem?

I hope this doesn't come down to reinstalling Win7 (and I'm not sure if that's going to solve it...).
Thank you for the help!

EDIT:
To note, I don't see the router, and consequentially the internet neither of course. Also, I barely see the internet connection at the back of my PC blinking. It's on, but hardly sending stuff.

Thanks for the reply!

When I entered the command "ipconfig /release" and pressed enter, it showed: "Windows IP Configuration" and then the CLI freezes. It looks like it still is busy, or it just usually takes long, but it never finishes where I can enter a new command.

I guess something is wrong with the driver or with the hardware...?

Thanks

Thanks for the replies guys, however when I turned my PC on yesterday, the internet suddenly worked again. It's really weird, it just didn't work for one full day =/ (even after like 100 reboots).

I'll try the repair next time it acts up (probably next month =/)...