Power user acsess rights

Right, I have a customer who has about 15 laptops all running winxp pro. each machine has the users setup on them and they are all set to poweruser level. However, they cant install certain programs such as nero burn, and im wondering which security settings I would need to change in order for them to be able to install all software?

I cant set them up with Administrator privlieges as there in some security software installed, and this would enable them to by pass this with out using the usb security key that each user has.

Anyone out there with any ideas?

Cheers

Chris