Open Network drive without mappping the drive

Hi

I have the following code to open up a network drive and then folders and then a user can select which file he/she wants to open.
The user must be able to select which file they want to open.

ChDrive ("Z:")
ChDir "\\Folder1\folder2\folder3"

the problem is that Z: is a mapped network drive, that will be a different letter for different users and i need this to run from multiple users computers.
Is there any way i can get this to open a network drive without mapping the drive because its obviously going to cause problems for other users.

Thanks

I am using XP
I have tried that, it does not work
I get a "invalid procedure call argument" error
Is there anything else i can do

Thanks,
It works beautifully