Thanks,
Here is another site that users might want refer to :
http://www.computerhope.com/issues/chsafe.htm
As an XP user however, there were several occasions when the F8 option failed for some reason - in that instance anyone using XP might like to try Start > Run type MSCONFIG - click Boot.ini tab at the top of the interface that appears - then click Safe Mode box under Boot Options.
It can take a while to restart in Safe Mode but it does work.