Windows Vista Dhcp-Client 1001 error

> Help!!! I'm connected to a public wireless network, but days ago the
> signal
> started to had problems. Before the computer had strong signal, but in
> days
> the signal is poor and when I checked Event Viewer has this errors:
> -Your computer was not assigned an address from the network (by the DHCP
> Server) for the Network Card with network address 00210022B763. The
> following error occurred:
> The semaphore timeout period has expired.. Your computer will continue to
> try and obtain an address on its own from the network address (DHCP)
> server.
> -Your computer was not assigned an address from the network (by the DHCP
> Server) for the Network Card with network address 00210022B763. The
> following error occurred:
> The operation was canceled by the user.. Your computer will continue to
> try
> and obtain an address on its own from the network address (DHCP) server.
> Please help me.
> Thanks!!!
>
>