The problem could be it's 'Vista'
Did you uninstall ZoneAlarm? Check in taskmanager 'vsmon.exe' is not running, if so kill it and delete it from 'C:\Windows\System32\Zonelab', I think it lives there or search for it!!
Try resetting all the browsers to their default settings, may be a security setting?
Check there are not 2 firewalls/antivirus running? I've had laptops that have AVG/Avast/MSSE all running together!!!
Did it have McAfee on? Most laptops I see have it pre-installed, if so go to McAfee and download their removal tool and run it:
http://download.mcafee.com/products/...tches/MCPR.exe
Can you log onto another account on the laptop and see if that works, or create a new admin user and log on as that and see if it works! If so their profile is knackered! You could then try the 'Windows Easy Transfer' wizard to backup the account data and copy it to the new account and see if that works also.
Having to do 2 x 12hrs is not ideal when dealing with problems, I've a mate who does 4 x 12hrs and 4 off regular.
Only recourse if all else fails is backup/re-install!