See if this Samson article helps:
Using the Samson USB Microphones with Windows Vista.
When first connected, the microphone
gain setting will be rather minimal,
and will need to be turned up.
To do that, go into Control Panel -> Sound, Levels tab, which sets the computer controlled gain or mutes the microphone:
Given that the driver you are seeing on Windows 7 is not the same as Samson says you should see on Vista, and given that Samson doesn't have any installable driver but instead relies on the driver automatically installed by Windows, then there is only one solution I can think of: Install the Vista driver on Windows 7.
To do that requires a driver backup utility, such as Driver Magician Lite, and access to a Vista computer.
The idea is to connect the microphone to Vista and let it install its driver. Verify that it does have the correct Levels tab. If it does, install Driver Magician Lite and use it to dump the (correct) audio driver. Bring it over to the Windows 7 computer, go into Device Manager, Properties of the audio driver, and install this driver.
The Vista and Windows 7 driver models are identical, so this should work. However, create first a system restore point before changing the driver (even though there is normally a Rollback driver button).