It depends where you are. If you're in a Starbucks, it's probably public access. Just remember that whoever has that router COULD have made it secure, so it's safe to assume they don't care you are accessing it... that's my point of view, anyway.
Windows Defender: useless as tits on a boar. You can deactivate it with start up manager (either Ace Utilities or msconfig)
You're using XP? You can change your power options through Control Panel. Personally, I hate hibernation. You might want to mess with just shutting off the display after "X" minutes, and shutting down hard drive after "X" minutes. It all depends on if you use the battery a lot.
I'm a deep well? Naw, but I know plenty of people that would love to toss me down one.