Hi , I had this problem and i did the research ,like you do and came up with what most people did ( clean and take out ram and other things that you have added to the computer then put them back in) and this did not work ,but the Re: 927-Non Fatal FSB Error on Front side Bus 0 changed to a Re: 927-Non Fatal FSB Error on Front side Bus 1 , mmm then i realised i had not put things back in the same places . Yes it was a usb card not working . Happy days as the computers works. So try taking out all the extra cards you put in , except the graphics card and work 1 by 1 to see which 1 does not work.
PS this is the computer that had the fault and its working great.