BleepingComputer.com: Windows Vista fails to start

Hi,
I recently posted a Windows Update problem (Toshiba Satellite, A100-049, running Windows Vista), and although member Broni provided assistance the problem was not resolved. Further references on Microsoft site indicated there might be a registry problem so foolishly, as it may now prove, I used an online registry cleaner tool. Following the clean up all appeared ok for a couple of days, although did not have the chance to check for windows update, then my daughter advised that the laptop would not start. Part way through the start up (approx 80% on the bar graph, the screen displayed Windows Error Recovery, with the message, Windows failed to start. A recent hardware or software change might be the cause. It provided two options:
Launch Startup Repair (recommended)
Start Windows Normally

I tried both, but screen just reverted straight back to same message. I have also tried to go to Safe Mode (F8), and have attempted all options, but once again although it runs through the startup, it reverts to the Windows Error Recovery screen.
As my daughter has had the laptop sometime she cannot remember if she had any Recovery discs. However, it appears there may be a built-in recovery application on the hard drive, which can be accessed by pressing and holding the 0 (zero) key on startup. However, she does not wish to lose all her data files (docs/pictures etc). Is there a simple solution to the problem or am I faced with re-formating to factory default settings? If this is the case how can I extract/transfer all her data without losing it? Ay assistance would be gratefully received.
Thanks in anticipation.
Mel