Why is my disc not spinning

Here's the way that this works:

1) The laser starts up to "detect" that a disc is present.

2) Assuming that the disc is there, the disc will try to spin while the system attempts to read the Table of Contents (TOC) off of the disc.

Since you state that the disc won't spin, I would suspect that the laser has not determined that the disc exists.

You might have a defective drive.

If you can gain access to the laser lens, try cleaning is using a cotton swab and alcohol. be gentle as the lens is supported by very fine wires that allow it to focus.

Dan