There have been a number of reports of this problem
On userlogos here
On the web here
This problem is not only experienced with Fast Dial, but with other extensions too,
as can be seen from these posts, the problem is being caused by Norton.
It would seem that Norton is deleting the file extensions.rdf in the Firefox Profile, on reboot of the computer.
This is being done to ensure that the Norton Firefox extensions are loaded into firefox.
The method used however may work for Norton, but is invasive and disruptive and works in a ham-fisted manner.
For the moment I have not heard of a fix of this problem coming from Norton.
Some users are removing the Norton extensions and then making extensions.rdf read only.
Might work short term, but is not that convenient.
But neither is reloading extensions after every computer reboot !!! :-)
Let us hope that Norton come up with a fix quickly.
Tiresome....