A friend with a vista PC was having problems connecting wirelessly to a
router. It had been working OK for months then she decided to download the
MS Office 2007 trial. Since then her wireless connection stopped working
(though I have no idea why this happened at this time). Their other
computer was also having a really slow ethernet connection so I had them buy
a new cisco wireles router with his new PC. I told the Vista machine to
connect to the new SSID but I had set up WPA on the router and vista didn't
have that option. So then I changed it to WEP on the router but vista said
it couldn't connect. A help menu had me run some netsh commands about adhoc
and infrastructure but it still didn't work so I rebooted. Now the vista PC
doesn't even see any wireless networks available, but a laptop I tried as a
test still sees three SSIDs including the new one.

What are my troubleshooting steps in vista to find out what is wrong with
her wireless connection and how to fix it?
And how can I find out what is still making the network still slow - the
other machine is brand new with WinXP?