ISP change, no connectivity

could do with some help here if anyone's got a few minutes free?

changed ISPs but I can't connect using an XP system

A windows 7 system has never been connected to the old ISP and is connecting fine to the new ISP.

XP:

this system is connecting using a Buffalo USB wireless adapter (WLI-U2-KG54L)

when the connection manager (Buffalo Client Manager 3) attempts to connect to the new ISP, the connect state returns 'Limited or no connectivity

The connection is marked at 100% from the USB key to the WiFi device

The mac address is identical to the old ISP mac address

The IP address when connecting is 0.0.0.0


The new ISP:

this is an E-Mobile Pocket WiFi LTE mobile internet connection


Do I need to 'flush' the old connection data from the XP system or something along those lines?

I'm clutching at straws to be honest.

The thing is, when I try to reconnect to the old ISP, the same thing happens as in, it returns a state of 'Limited or no connectivity' and can not retrieve an IP address until I restart the system after which, it connects to the old ISP fine.

cheers for any help in advance.

 

We'll need to take this 1 step at a time.....