Fix Default gateway??

Hi; I am DEFINATELY a newby at this but, I NEED HELPPP! My "default gateway" keeps going down, and I want to know how to prevent this?? Also, is a "system administrator" Me, or someone else? (Keep getting a "contact system administrator" message.) Finally, just bought a used computer and it seems to want to be part of a network between itself and my old computer, (or another one at any rate) I dont' NEED or want a "network! I'm only running the one computer!(X-P pro) Any help you you can give will be Gratefully appreciated!










helppp1 with "default gateway!!!!"