Hi,
Even though this is an old issue, thought id post this here for future reference.
I have the same TV tuner, the drivers can be found here:
Driver
(Under PCTV 70e)
To install the drivers though, you need to manually open device manager and update the drivers.
Right Click "My Computer" > Manage > Device Manager > Imaging Devices > ET USB 2750 Camera > Properties
Then in that window go to the Driver Tab, then click Update Driver
Select "No, Not this time" for windows update if it comes up
Select "Install From A Specific Location"
Select "Search for best driver in this location"
Select "Include this location in search" and click Browse..
Navigate to where you extracted the drivers you downloaded
Click Next
And it should update the drivers.
The TV Tuner will now come up in windows media center for use!
Note that I did a few steps from memory as I am at work, but I'm sure you will get the idea.
I did this on Windows 7 Professional 64bit, and it worked perfectly.
Hope that helped,
Perrin