Does this happen on every site, or just certain sites? Which browser are you using, and what operating system?
You could try disabling your antivirus / firewall and see whether that makes a difference.
There was also an issue with protected mode in the trusted sites zone that caused this.
Do you keep your browser up-to-date? Running Windows update (assuming you're using Windows) could possibly fix this. Even if it doesn't, running it won't do any harm, as it's a good idea to keep up-to-date with the latest patches.
