Hi
Well i can only say how i got my phone to be seen by Win 7 64.
1)Uninstall Kies
2)Went into regedit and searched for all files with KIES, and deleted them all.
3)Rebooted laptop
4)Backup the internal files to SD card, synced my apps with appbrain.com (as easy to see what was installed and to reinstall) ***then unmount and remove external SD card***
5)Format internal SD
6)In settings set USB connection to Ask
7)Plugged in usb cable to laptop and phone, choose Mass Storage
8)Win 7 64 installed the basic drivers, and i could see the internal SD as a removeable drive.
9)Unplugged cable from phone and replugged back in.
10)Choose Kies (***this is without KIES being on laptop***)
11)Watch as Win 7 64 installed the MTP USB Driver (the bain of my life) and another driver and watch as the pop up screen on laptop asks what i want to do (list of things, choose view phone)
12)Now you can see a phone icon in My Computer with GI900
13)Install the latest version of KIES.
14)Kies finds phone (as the MTP USB driver is already succesfully installed at stage (8 + 11).
15)Now starts the process of backing up from Appbrain and External SD card.
16)Have a beer or two to celerbrate
Now this worked for me, as I have tried different usb ports, uninstalling and reinstalling KIes, downloading many samsung USB drivers and still getting the mtp screen flash on and off in a mocking gesture.
)
