I went through the start-up procedure again and this time the repair procedure advised "Windows cannot repair this computer automatically" - two link choices available: Ist Choice - 'View Diagnostic and Repair Details': This confirmed the last successful boot time as 2/7/2013 7:14:23 PM GMT which tallies with the last good performance on Thu evening. Scanning through the multitude of Tests it had run revealed that all were completed successfully, but the final log entry read - Root cause found: Unspecified changes to system configuration might have caused the problem. Repair action: System files integrity check and repair. Result: Failed. Error code = 0x2.
2nd Choice - 'Advanced Options for system recovery': This gave me a box to choose the recovery options and identified Operating System: Windows 7 on (C:)OS.
A. Start Up Repair - No Good, as before and just ended back at the same place eventually
B. System Restore - No Good, Red Cross Message: There was an unexpected error - system cannot find file specified (0x800070002)
C. System Image Recovery - No Good, same error message as System Restore above
D. Windows Memory Diagnostic - Ran successfully, with no problems
E. Command Prompt - which give me a new box entitled C:\Administrator:X:\windows\system32\cmd.exe and a basic black screen Microsoft Windows [Version 6.1.7600] and X:\windows\system32 > "flashing cursor"
Not knowing what to type next, I have this morning (Sat) tried booting from the Windows 7 Backup disc supplied and the Dell Drivers and Utilities disc supplied, but to no avail in both counts.
At this point (having finally persuaded the [bleep] DVD drive to give up the disc!!!)I tried another restart and this time it went into a screen 'Intel ® Boot Agent GE v1.3.10' and gave the following screen info: CLIENT MAC ADDR:00 21 70 58 B9 6E GUID:44454C4C 3300 1039 8043 C$C04f474631, then PXE-E53:No boot filename received, then PXE-M0F: Exiting Interl Boot Agent. No boot device available.
And thats where I have got to - gazing bewilderdly at the above paragraph on the screen with the cursor blinking in front of me !!!!
Sorry if that's all a bit long winded, but I figured the more relevant details I could offer would help you more knowledgeable guys out there. If it turns out to be a hard drive problem rather than software then I am resigned to starting the Windows 7 re-install from scratch, but as my last back up was 8 Dec 2012 (I know - slapped wrist and all that!) I would like to rescue my files off the hard drive before wiping the disc.
Hope someone can help!