Unable to run ArcMap 10.1 for Desktop

I'm a ArcMap 10.0 user and tried to install the new 10.1 upgrade. Unfortunally i get errors when starting the program. Our ICT backoffice did a repair and to my own suprise it worked. After restarting my laptop the error returns. Someone from Esri adviced to install SP1 for ArcGis but it didn't help.

I'm using OS Windows XP.


Best regards,

Robert Schuil
The Netherlands