Johny C - - -this is an absolute piece of cake mate - - -- have done it myself with guides from this forum but here comes the rub, can't remember what order what was done, when !!! ( what a prat I hear you say - - - well, say away !!). I stuck my 2nd hd as slave to primary, fortunately the cable was already there for this. Make sure jumbers on this new drive are set to slave. Will try and look up sequence for you my my own PC is working properly - - - -some idiot screwed up fixing 2nd hard drive - - - only joking mate.
My configuration is : -
60gb hard disc on primary/master
40gb hard disc on primary/slave
DVD-CD ROM secondery/master
CDRW on secondery/slave
sorry I'm a bit vague, problems of me own right now but if no further help comes from this thread, I will look up the stuff I had when I did mine