Adobe Reader X Help (F1) will not open. The message I receive is: "Online Help content cannot be displayed. Verify you can launch your web browser and have access to the Internet."
no antivirus installed
IE 8/Mozilla Firefox 3.6.13
Protected Mode Enabled and Disabled
Reader X does not ship with a help function other than Internet-based help. There is a downloadable "help" PDF for reader X that can be referenced, but it is not accessed with the F1-Help function. Maybe they will fix this some day.
Is your computer behind any firewall, Such as ISA or TMG. We had a similar issue and it has got resolved by installing ISA firewall client. Since the Adobe help uses anonymous credentials to access the internet and its getting blocked by ISA servers.
Hope this will help.