The PC was built by a private manufacture who supplied an OEM disc which contained Windows 7.
I altered the BIOS (F8) - Boot Order to make the CD first and placed the CD into the drive. PC was shut down and re-started with the Windows loading screen followed eventually by the option to either upgrade or install Windows 7. I selected the complete install which as part of the process re-formatted the hard drive.
After Windows 7 installed the only drivers
I needed to install were for my monitor. I'm not completely sure but perhaps by actually altering the BIOS to boot only from CD prevented this 'going around in circles' that both you and I have experienced at the start up phase!
Hope this helps!