Flash Player installed but not working

[nickpana]

Flash player seems to be normally installed on ie8 (Vista OS), but in some pages I recieve the prompt "Install add-on Flash player".

The picture above describes this perfectly: The add-on is installed correctly (the version on the right is correct) while the yellow bar pompts for reinstallation.

The account used is an user account.

The same page is displayed perfectly when I change to admin account

[nickpana]

This is the image of the add-ons manager. Flash is installed and enebled