Networking and ADSL connection problems

From my laptop I cannot get connected with my network at work anymore even though I can get connected to the internet through the work server. The problem started about 2 weeks ago after I re-installed Windows XP Professional on a new replacement drive. The network started fine after the new install but after a couple of reboots it stopped being able to see the other computers on the network. At the same time at home my auto ip addressing does not work nor does ipconfig/relese releases the ipaddress in order to renew, so that I cannot get connected to my ADSL modem. At work ipconfig/release works returning IP Address 0.0.0.0 and Subnet Mask 0.0.0.0 then ipconfig/renew renews my IP address. I have inserted a PCMCIA 10/100 card but still the same problem through it. I have tried to do a repair to my Windows XP with a Windows XP Repair re-install but again the same problem. Worked for the first 20 minutes or so but after another reboot...no network -again.
Help........

Addition to previous (if it helps):
I can ping and get replies (4) from other computers on the network with the same results:
Reply from "ip address...": bytes=32 time<1ms TTL=128