Flash Drive - Installation problem! - how to install FlashDrive without admin rights?

Hello,

I have to enable access to flash drives in one of computer. At this
computers are uses diffrend flash drivers, it's high number of diffrend
flash drivers uses in this PC. User have only "User" right at this PC (I can
give him "Power user" - it's max right that he can get).
Some times when I plugin flash drive all is ok, but some times user recive
information about installation new hardware and he need for this task
administrator rights.
How can I use new flash drivers without asking for administrator rights ?