MN-130 adaptor

I have Windows XP and I am connected with Microsofts MN-
130 adaptor and the internet was working fine until 1-week
ago. My Dad downloaded some anti-spyware program and then
all of sudden I no longer able to access the internet. His
internet is fine. When I went to XP's repair connection;
it came up saying renewing IP address. My computer support
says I have the internet but doesn't know why I cannot
connect. I don't know if the spyware program is the reason
but it is the only new thing that happened within that
time frame. Any suggestions? I have unplugged and
replugged the router, checked the connections, and have
even reformatted my hard drive but to no avail.