I've actually solved the problem although I'm not really sure what caused it. I run Windows XP Home. When starting up it went through the normal process until it got to the Windows XP page with the green dots scrolling across the page. Once that had completed it went straight back to the initial start page and then gave me the options for satrtup after a failure. Everytime it would get as far as green dots scrolling and go back to start. I then booted from the XP CD and ran an XP recovery. I've done this a few times before with no problem, however this time close completion of installation I got the following error message 'Procedure Entry Point GetIUMS could not be located in the dynamic link library MSDART.DLL'
I had to click this error message several times (probably more than 20!) before it cleared. Once it clear the setup finished and everything now appears ok. I would appreciate any info. Thanks