VISTA VS11+ security

[bill-xps410]

I guess I have some kind of VISTA security problem. Maybe someone with more expertise has some suggestions for me.

I capture a MPG from a capture card that only works on XP; so I have a dual-boot system. I capture the file then reboot into VISTA. I copy the file from the XP disk (small, only used for capture) to my regular VISTA, C: disk. I open the file in VS11+ and edit. When I try to then "share move", I get an error message that the file is "write protected". I look at the properties and security attributes from windows explorer and they appear to be set correctly. My user account has ownership and that accout, as well as the administrator group, have full control. I don't understand how this happened.

Thanks for any advice.