Permalinks not working

Hello,

I’ve started a new blog en want to change my permalinks. But even what I try I can’t get it working. Ik would like to change the permalink ‘/?p=123’ to permalink ‘/%category%/%postname%/’. I changed it in the wordpress control panel but still not working. Even edit my .htaccess en trying some plugins was not successfull. WordPress is running on an Windows server.

Can someone help me?

Already thanks,
Christiaan