I/O operation, registry failed unrecoverable error msg

I was recently having problems with getting this error msg when
starting xp pro:
"An I/O operation initiated by the registry failed
unrecoverably. The registry could not read in, or write
out, or flush, one of the files that contain the system's
image of the registry"

I have seen a lot of people having a simular problem and would just
like to share my solution. My bios was set to recognise raid
controller when I didn't have one. Once this option was disabled my
problems dissapeared.