OK.
I will take the case off (well open the door ) and check the CPU fan and stuff is OK.
I can get the PSU repaired here for £40:
http://www.cpsupport.co.uk/quicksilver.htm
And as the hard disc is an ultra IDE 66 something, I can get one of these and turn the hard disc into a USB drive, no sweat with MAC OS X......
http://www.ebuyer.com/product/136250