Uninstall the driver AND the included software. Reboot your system. Windows should attempt to locate an appropriate driver for the device on reboot. If it does, go back into device manager and make sure the exclamation mark is gone.
At this point, DO NOT install the included software. Instead, check to see if Windows Media Center see it (assuming you have Windows 7 Home Premium or Ultimate). If it does and works well, you're done. If it works but seems flaky or stutters (or Windows failed to find drivers on reboot), then attempt to install drivers from Sapphire (again, do NOT install the software app from Sapphire) and see if performance improves.
Let us know how it goes.