Hi,
The Dolby feature you mention should be installed by the IDT software package, no seperate download is required ( or available ).
Let me know the following:
1. What is the full version of Windows installed on your notebook?
2. How was the original IDT driver deleted - ie from the entry in 'Programs and Features' or from Device Manager?
3. Open windows Control Panel, open Device Manager, expand Sound, video and game controllers, right click on the IDT entry and select Properties and click the Driver tab. What is the Driver version shown here?
Regards,
DP-K