Hello,
  Thanks for all the advice,  at the moment I am working my way through this web site.  
http://forum.pcmech.com/  some good advice, 
 I had a dual PIII built about 4yrs ago with NT4 workstation, mostly running 3D software/photoshop although photoshop does not take advantage of dual processing. 
 I tried to setup a Dual boot with 98/NT and XP pro, as XP pro would take advantage of the dual processors and networking to a Mac. 
 But I could never get xp to boot. . .
 I suspect because of the Mother Board/ device conflict. 
 The motherboard is by todays standards old hat Gigabyte GA-6BDX and maxed out with Dimms Ram. (which I will not be able to use on the new Mother Boards) 
 As pointed out I could buy a complete system, but as before I like the option of upgrading if and when needed. 
 I hope I am right in saying that my biggest spend should be Processor/Motherboard/Graphic card. 
 Then HD ( which I can take out of my excisting PC) /Memory/Power Supply/Fans. Case I can use. 
 Cheers Robin when I have a list together I will email you. 
 Thanks again all for the info, at least I now know who to ask. 
 regards 
 TopiToo