Black screen while booting despite using Thinkvantage Button

[recyclebin5]

Hi
Helped a friend yesterday with headlined problem (see above). The problem appeared to be related to the Presentation Director (Fn+F7). So I connected an external display and that was that. Easy solved when U can see...... (XP Pro, Z-Serie)

The question: While booting I used the blue Thinkvantage button but obviously this simpel presentation facility overrides the vital Rescue & Recovery's workspace to show up??? How is this possible? May the R&R facility be deactivated? If so, how do you reactivate it again? If I didn't had another display nereby this would not been solved. No actions taken with the Presentation function before the problem started. Just appeared by it self.

Grateful for any explanation! //Pc