Thanks, all,
I am running WinXP Pro.
I had connectivity problems from the start, even before I downloaded the Windows Updates. Fortunately, when I can connect wirelessly, the connection works well, so that if I need to download new drivers, I should be able to do it.
Before that, I think I'll reboot the modem and router, and delete the old network connections and create new ones. It just occurred to me that there may be something funky going on with the router and/or modem because I set up the original connections when I still had the ThinkVantage Access Connections software installed.
I checked and the timezone settings were correct. I will definitely try to change the clock in the BIOS.
Also, I've noticed that, since the incident Friday when I had to remove and reinstall the battery, my battery guage never reads higher than 98%. (I'm always connected through a surge protector, haven't tried to run on the battery.)