I Lost My Secure Connection

I've had a wireless card on my laptop for over 3 years, home networking
with roadrunner.
I began having problems losing the connection several times an hour and
called the cable company and I was informed that my next door neighbors
wireless signal was conflicting with mine. I also found my neighbors
documents on my laptop in my network places!

The tech helped me to make my connection secure and gave me a "key".
Everything was fine for a few days, then my connection began dropping
from 11 Mbps down to 1mbp. I went to my control panel and opened the
Prism settings and clicked rescan hoping that would correct the
problem.

Now, I no longer can get my secure connection with my name and
encripted key....all I get is a choice of a secure connection (not
mine, and it won't connect me) or an unsecure connection that does
connect but it keeps changing itself back to the secure connection and
then I have no signal.

If you can make any sense of what I'm trying to say, I'd appreciate any
help.
Thanks