Windows File Protection at startup? (Real PLayer??)

[A C]

I have a Dell laptop with XPHome, and after installing things that I
generally need onto it, I soon found that most times that it started up
it presented me with a window:

=================================
Windows File Protection
Files that are required for Windows to run properly have been replaced
by unrecognised versions. To maintain system stability, Windows must
restore the original versions of these files.
Insert your Windows XP Home Edition CD ROM now
'Retry' 'More information' 'Cancel'
=================================

Either the CD has to be used (no option to refer to a file on the
laptop) or one proceeds with the poor stability system.

A search of usenet suggested that RealPlayer might be a possible cause,
so I uninstalled it.

The problem went away, and stayed gone.

I find it hard to believe that Real Player (Basic) is not compatible
with XP Home, and wondered what to do next to (maybe) get Real Player
back onto the laptop so that everything functions?

 

[Guest]

realplayer can be the issue.

 

[A C]

realplayer can be the issue.

Thanks, it is reassuring to know it is not me.
Any suggestions about how I could investigate it (can something like
event log etc be used?), or what combination of circumstances are
sensitive?