Why hit F1 to continue

[SS]

On my wifes PC for some reason when booting up it now asks "press F1 to
continue` it never used to do this and previously would just boot straight
through to the desktop.

I presume a setting has changed, what do I change to get this back.

thanks

 

[SS]

Now sorted, it was a loose cable to the DVD drive (dell flat PC)
apparently a known problem for that model.

Anyhow sorted.

thanks Philo