Firefox restricted from opening

I have been using Firefox for a long while and recently (some time last week, if memory serves) upon trying to open FF I received a 'Restrictions' message stating:
This operation has been cancelled due to restrictions in effect on this computer. Please contact your system administrator.

I run FF from the admin. profile on my laptop and I have not restricted any programs. I tried uninstalling FF and then downloaded and installed the latest version (3.6.2) and the browser opened automatically after installation. However, after closing and attempting to reopen FF, the same Restrictions message occured.

Any help/info/direction woul be greatly appreciated, especially as I know very little about what I'm doing....

 

Yes, however the problem occured before I updated. After it happened I thought an uninstall/update might fix it, but no luck

EDIT:
I donwloaded and installed Google Chrome but received the same Restrictions message when trying to open it. At the moment IE is the only browser I can use and, for obvious reasons, would like to go back to FF asap

 

Having been working with related programs for, at least ten years, I can say that

have never fixed any problem. Since Firefox, like the older Mozilla and Netscape are made up of, at least, two separate components, the program (the one which uninstall/update) and the profile, which is not affected by uninstall/update, I can say that the old potential fix is to create and use a new profile.
But, I never got any restriction issue, but if you google "firefox restrictions" you will get a lot of hits. From what I can see, there may be some other program involved.