a question
 

does anybody know about an imagedrives program which can run on non-admin rights on xp?

Are you talking about virtual drives like Daemon tools? I don't think you can if you don't have the admin rights unless you can bypass that security somehow.

the situation is: there is a pc with user rights only. how can one person mount an image to the machine. in case of isos i could extract it and use subst commandline command but in case of other images with protection i'd need a prog

I dont think this can be done without administrator rights. At least not with Daemon tools and the like. They look to the system like a new drive, after all, which has to be installed using drivers and such. So I am afraid you will need admin rights to install it.