No valid disc message displayed. Disc is spinning.

When a DVD player starts doing that, it either needs to be cleaned, or something is going wrong with the DVD mechanism inside of it. You can purchase DVD lens cleaner from any large retail store that has an electronics section. However, if you clean it and the problem persists, it will likely be cheaper to replace the unit rather than trying to have it repaired unless you're under warranty in which case any repair or exchange will be covered by said warranty. If you call the manufacturer they will give you your full range of options.
I hope I've provided you useful assistance and that this information allows you to make an informed decision as to how to proceed from here. Please be sure to vote on my response. I hope I've earned a good rating from you today.

Please post a comment if you need additional assistance so that I can help you further.