WiFi Networking Vista Ultimate

I have a problem that started recently. My network notification stopped
working and is showing a server exception. It was working for connecting to
the WiFi network, even though it did not show this. This all began around
the end of October. Now within the past few days I am unable to connect to a
network without restarting the computer 5 times. Each time I have to clear
out the Prefetch and Temp folders. And it is still hit or miss on the
connection. I would like to know how to fix this without having to reinstall
Vista. Expediency on this would be helpful, but not required. I do need an
answer though.