After a failed download of Returnil Virtual System yesterday on my PackardBell desktop computer (am writing this on my laptop),the computer closed and started with a black screen showing possible causes for Windows being unable to start and highlighting 'START WINDOWS NORMALLY' together with a counting down till restart.However each time it goes through the 'start windows normally' procedure it fails and the same black screen appears with the same explanation.
I have also tried in turn highlighting two of the other possible choices:-
'LAST KNOWN GOOD CONFIGURATION'
&
'SAFE MODE

Both had the same result ; the black screen returns with 'START WINDOWS NORMALLY' highlighted and counting down.

P.S. I am English speaking but my computer is set up in French so the above is a translation.

Have you tried booting to Safe Mode ?

When I boot to Safe Mode I get a page :-
Boot Menu
Select & Boot FIrst Device
Hard Disk
_NEC DVD_RW ND- 3530A
Realtek Boot Agent
Mode Enter Accept F9Exit

That's boot options, not Safe Mode.

When you start up your machine, just after the makers splash screen, hit f8 repeatedly.
If you get the Windows screen then you need to start over.

When I hit f8 repeatedly after the makers Splash Screen that is what I get i.e. boot options

A dirty way of accessing it is to let the windows spalsh screen to come up and pull the power.

Unfortunately pulling the power did not work I neither get 'boot options' page or a page ' Menu of Advanced Options for Windows XP'... Select an Option...

Sorry Curlyben that should read 'I either get'

I have now got into Safe Mode Page!
Choose System to Start
Microsoft Windows XP Family Edition
Recovery Console Microsoft Windows XP
Press F8 for Advanced Start Options.

Which do I choose ? I tried ' Micosoft Windows XP Family Edition' and it did not work.

After trying ' Recovery Console' I am pleased to say that much to my delight Windows has started !
My thanks for your help Curlyben.