WiFi Problem in Thinkpad R40, 6 yrs old

[BillPhillips44]

My six year old Thinkpad R40 still does everything I need, though it's a little slow. The WiFi connection works fine at my home, but sometimes in another person's home, it will not connect. It recognizes the WiFi signal, but will not give me a window to enter the home's password. I get an obscure message, which I don't recall.