I have the Same issue as few user. The youtube videos is blocked by Zone Alarm.
I try to use diferent browser (Explorer, Firefox, Chrome) but nothing changed.
After reinstall everithing, but that also not helping on my problem.
One of my friend told me try the Firewall, and he is right.
I read "xdwall" thread and try to disable the " Identity Lock to "Off""
After my problem is solved
ZoneAlarm Extreme Security version: 12.0.104.000
Vsmon version: 12.0.104.000
Driver version: 12.0.102.000
Antivirus engine version: 188.8.131.52
Antivirus signature DAT file version: 1143170368
AntiSpam version: 184.108.40.20673