I too am running into an issue with Windows 7 x64. I have no option to remove the files when I uninstall the driver, and Windows tells me that it can't find any drivers. I've pointed to the root, and the amd64 folders. Windows automatically installs some kind of driver, because I see both the TF300T and GT-N7105 devices under Portable Devices. However, they also show up under Other Devices with exclamation marks, indicating they don't have drivers installed.
I've tried choosing a device, and I still see Samsung drivers are installed.
How can I remove the old drivers?