Can you ping your isp's gateway..... heres how:
Without a Router--------------
Click on START
Click on RUN
Type in: CMD :and press ENTER
Whn the black window appears type in: ipconfig :and hit enter
you should get three lines of information back; IP Address, Subnet Mask, and Default Gateway.
Now type in: ping 68.12.34.165 :where 68.12.34.165 would be the address you received for default gateway in the last step - I just put mine in to show you how.
Copy back you results
With a Router---------------------
Click on START
Click on RUN
Type in: CMD :and press ENTER
Whn the black window appears type in: ipconfig :and hit enter
Copy down the default gateway address and then minimize this window
Open internet explorer and in the address bar type in the default gateway address i had you copy down in the last step and hit ENTER
This should take you to you router configuration utility where you will get a page or window asking for your username and password.
Here is a list of default user names and passwords if you don't know yours.
After step 43.Once the correct user name and password is entered you want to navigate to the STATUS section and locate the default gateway listed there (this is your actual ISP's gateway)
If you are unable to find it STOP here and post back your routers make and model and i will post specific instructions for your router on where to obtain it.
Once you find it, copy it down, and maximize the black window i had you minimize earlier
From the black window type in: ping defaultgateway :where you would insert the address i had you copy down in the last step.
Post back your results