If the computer having the problems is running Norton Internet Security, take a look at the Symantec page,
Cannot access or log on to secure Web sites with NIS or NPF .
You could also try:
1. Go to your Internet Explorer>Tools>Internet Options and delete the temporary files and cookies
2. Click on "Security" tab.
3. Then in the box that says Select a Web content zone to
specify security settings, click Internet Zone.
4. Click on "Default Level" tab.
5. Drag the Security slider to "Medium-Low" level.
6. Click on "Apply" and "OK".