How do I enable my DNS Cache and my DHCP? I am having internet issues.

I have been looking everywhere to no avail. None of the things, hotfixes, registry editing, flushing or reseting of my DNS Cache has fixed this issue I have been having for the past week. I have been able to connect to the internet but it is so much slower than usual. I have already contacted my service provider and they are not the problem. Here is some info: My computer is a Windows 7 Ultimate 64-bit connected at a 15mbps down speed and a 3mbps up speed through Comcast. And here is what shows up when I type ipconfig /all in the command prompt with admin permission:

C:\Windows\system32>ipconfig /all

Windows IP Configuration

Host Name . . . . . . . . . . . . : homecomp
Primary Dns Suffix . . . . . . . :
Node Type . . . . . . . . . . . . : Mixed
IP Routing Enabled. . . . . . . . : Yes
WINS Proxy Enabled. . . . . . . . : No

Ethernet adapter Local Area Connection:

Connection-specific DNS Suffix . :
Description . . . . . . . . . . . : NVIDIA nForce 10/100 Mbps Ethernet
Physical Address. . . . . . . . . : 44-87-FC-7A-E2-3B
DHCP Enabled. . . . . . . . . . . : Yes
Autoconfiguration Enabled . . . . : Yes
Link-local IPv6 Address . . . . . : fe80::fdb0:53d0:bb4a:806f%16(Prefer
IPv4 Address. . . . . . . . . . . : 192.168.1.9(Preferred)
Subnet Mask . . . . . . . . . . . : 255.255.255.0
Lease Obtained. . . . . . . . . . : Thursday, November 17, 2011 9:39:48
Lease Expires . . . . . . . . . . : Friday, November 18, 2011 9:39:48 P
Default Gateway . . . . . . . . . : 192.168.1.1
DHCP Server . . . . . . . . . . . : 192.168.1.1
DHCPv6 IAID . . . . . . . . . . . : 272926716
DHCPv6 Client DUID. . . . . . . . : 00-01-00-01-15-2A-E1-43-44-87-FC-7A

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

Tunnel adapter isatap.{8D9B809C-5D6A-4C5F-B3A0-E3CEB3FED1C4}:

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* 12:

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

Tunnel adapter 6TO4 Adapter:

Media State . . . . . . . . . . . : Media disconnected
Connection-specific DNS Suffix . :
Description . . . . . . . . . . . : Microsoft 6to4 Adapter #3
Physical Address. . . . . . . . . : 00-00-00-00-00-00-00-E0
DHCP Enabled. . . . . . . . . . . : No
Autoconfiguration Enabled . . . . : Yes

My IPv6 use to be connected and worked just fine but as soon as it disconnected my computer shows thisattached image) saying I have no connection but when I scroll over it with my mouse it says I am connected. I have tried virtually and physically almost everything to fix this issue but I need somebody smarter and who knows more about this type of issue to help. If you need anymore information I would be glad to supply it.

I tried to install the Nvidia network access driver version 15.35 from their site and i got fatal errors during the installation but I'm sure the other things that came with it installed. I am still having issues with my connection its still slow as it was yesterday and the IPv6 still hasn't been able to connect. I think the issue may be internal look at the screenshot I attached it says the IPv6 isn't connected. Before these issues had started my IPv6 was connected and my internet speed was smooth and fast, my connection status on the bottom right corner also didn't have the red X through it. Do you think there is anything I can do to fix my DNS cache? Or my IPv6. Thanks for the fast reply by the way.

Sorry here is the image I mentioned.

There is usually only 1 other person in the house using the network at the same time but not as often as i do. I use Avast Antivirus with Internet Security and I have never had any problems with that. None of the other computers have the same issue. I think the issue started when I changed some internet options a little while back but I do not recall what they were. What I would really like to do is delete my current connection and setup a new one but I do not know how to delete and internet connection, and when I try to make a new one it says: "It may take up to 90 seconds for unconfigured devices on your network to appear." Nothing happens even after 20 minutes of having this up. I will try to boot in safe mode with networking and tell you how it goes.

My internet speed is back to normal in safe mode so that excludes my hardware as being an issue. Is there a way i can restore to a previous version of my internet setting only? If there is not I will restore the whole computer.

I restored back to November 12th about 2 days before this issue started and the network connectivity icon at the bottom rights still shows an X through it. I just disabled Avast and my internet speed is faster than before, but I still want protection from internet attacks what do you suggest I do? Change Avast settings? Uninstall it completely?