Hi BambiBoomz
Thanks for the thorough reply.
When I did Write Zeros, Western Digital advised that this would overwrite all data and exclude any bad sectors from the disk. There were no bad sectors.
Not sure I can stomach another reinstall. It's really that bad. I've spent SO much time on it that I fear if I spend another day and end up at the same stage I will smash the PC up. I am normally calm but this has driven me to serious levels of anger.
By by the way, there is no need to apologise. None of this is anyone's fault.
I've spent a good hour or so today just looking for information on now to correctly set the BIOS for the best. All I can find is the xw4600 manual (176 pages) which doesn't really tell you what is right or wrong.
One thing I did read was changing the Sata Emulation from IDE, SATA or Raid after the OS has been installed can wreak havoc. Not sure why or whether I did change this because I probably changed it by resetting BIOS to default after I changed the CMOS battery. BIOS never used to affect things as bad as that from what I can remember. It's not as if it's and old IDE system with hard drives on the same cable!
One thing you've said strikes a chord. When starting install on clean drive, it automatically reserved a 100Mb partition called Disk0 Partion 1. OS was then installed to Disk 0 Partition 2.
None of the installations are OEM anymore because HP no longer have any genuine installations discs they can send because they have ran out because Vista is so old.