This thread has the software:
»Virgin Mobile USB Install Error, Help Anyone?
Many (including myself) have had issues downloading it (it seems the dslr site clips it since its so big) but if you use a download manager it should be able to grab it ( »www.downthemall.net/
is a good one for firefox).
I think the issue is that your machine has the "launch virtual CD" flag turned off so you never get the software presented to you. If you can't or don't want to download the software, you can also connect your MC760 to another machine and then copy the software over to a flash drive.