IP ConfigFatal Error***URGENT*

Need Urgent HELP!

Windows ME , network Protocol : Netbeui & TCP/IP!
Question:
Suddenly can’t ping any IP address , when in command prompt type > ipconfig /all , got a message ” IP Configuration Fatal ERROR “, But it can use network resource and it can view other computer in network niegbour .

i has tried re-intall NIC twice , and checked no
virus inflected ! when i assign a static IP ,
it can’t ping to other computer , when i ping 127.0.0.1 , it got ” error Code 10091″ .

PLS help ! URGENT !!!!!

THKS AGAIN!