Why wont my vista computer

Hi~ Thank you for answering all of u my question is Why is my wireless internet working see it was working for a while and me and my family's computer wanted to hook up to a network through Network Magic So i installed both network magics on both computers and it semmed to be fine until my family's computer said that i was offline so i went to my computer and then i noticed my interntet was not working so i right clicked on the internet connection botton on the bottom right hand of the screen and this time like no other time was there a little caution sign on the botton i clicked my wireless network and it said 'information sent over this network may be visible to others' ' Connect Anyway" so i clicked yes and it was loading then it stoped and said 'Can't Connect to the nelsons' so i pushed a botton that said "diagnose network' so i pussed that and it still didn't work can any of you help me please!!!!!
My Computer:
Windows Vista Home Premium/ Compaq
My Family's Computer:
Windows 98/ Gateway
Wireless router:
D-Link dir-615
SurfBoard Cable Mosdem:
Motorola sb501

P.S At First i thought it was a virus the one that is going around right now it even hacked CBS but i learned it wasnt that sooooooooooo.


THANK YOU ALL FOR HELPING ME!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!...