Noted at http://support.apple.com/kb/HT1710
There's plenty more to read about this.
My 2007 Macbook has just developed a fault... well, I'm not sure what it is!!!
1) My search tool on the top right hand corner of the screen has gone.
2) All my history in Firefox has gone.
3) Skype won't work.
4) All the links in Firefox have list their blue underlining and blue colour!
Now I've tried restarting the mac and I am currently backing it up, but has anyone got any clue??