VB.Net on USB Falsh Card

Question

I have written a small app. that needs to start when a USB flash card is inserted into the USB slot.  My app. uses an mdb file to a specific drive letter, say E:.  What do I need to do so the program will use use the mdb file regardless of the drive the USB falsh card starts with.  on some PCs the USB falsh card is the E: somtimes it is the F: and so on

Thanks