You haven't provided enough information for anyone to help you.
It can be very hard for a non-technical person to know what to include
in a post to a tech support newsgroup. Here is a link that will help
you with that - http://www.dts-l.org/goodpost.htm
After you read the information at the link above, post back with all
necessary details to get focused help.
You can't with operating system settings for plug and play hardware that
uses signed drivers even for non administrators. USB flash drives are a
possible example. There are third party programs such as DeviceLock that may
be able to help. --- Steve