Ben,
What error are you seeing at home?
Could be a dns or web browser hijack.
Try pinging
www.geocities.com from home. Report error returned.
Search your system drive, including all hidden and system folders, for
"hosts". The only legit one is in systems32\drivers\etc. Look
inside, using Notepad.
Check for spyware. Use HijackThis, Spybot S&D, and expert advice at
SWI Forums (all free). Complete instructions are available at:
http://forums.spywareinfo.com/index.php?showtopic=5187
Cheers,
Chuck
Paranoia comes from experience - and is not necessarily a bad thing.