Great - thanks for the input.
I'm also going to try a memory test as well on the pc - googling suggests trying that as it maybe a faulty memory DIMM and maybe removing the sticks of ram 1 by 1 then reboot. Will see what that throws up...
If that shows no improvement then I'll try the 3 time start-up repair again.
I'm edging towards removing the HDD with Vista on and replacing with a brand new drive to which I'll do a clean install. I can then restore the Vista data from the other drive using an external SATA cable I have @ home.