just a thought and it might not work or be of any value

I'm assuming you have XP or Vista

Click on start, click on run, type CMD.  You will get a black screen. Ignore everything there and just type what I placed below.  You will have no choice as to where to type.

Type ipconfig /release

Then type    ipconfig/renew

IF nothing happens for a long time, 5 or so minutes , press Ctrl + C  and that will stop the attempt. 

Type ipconfig /release    again.

Type exit to get out of the black screen.

Reboot your computer.

Now it should or might work.