Welcome to the forum
Probably you selected the wrong disc type. Try this method:
- Run nero
- Select the media type you want to burn (CD or DVD)
- Select Data disc (see pic)
- Select all files you want to burn on the disc (watch on the bottom line to be sure that you are not inserting too much files on the disc)
- Press the burn button
This should work
Another important thing: use quality media or there is the possibility that the burning can't be completed at all. Be also sure to select the right burning speed.
For 16x media, it is better to burning @12x or @8x.
If you still have problems, post here more details