About all you can do is clean the laser on the player to see if it starts to pick up the starting point on the disk. The laser needs to find this starting point to use as a reference for operations. The disc player may be bad and the motor for the spinner is not working and the laser therefore cant find the reference piont. Did you recenty move? sometimes these players have region codes associated with them for use only in the region it was purchased.
The player can be fixed if the motor is not spinning, but most simple dvd players nowdays are pretty cheap making a replacemnt a viable option over repair costs. Unless you have experience dealing with the small electrical devices, I suggest you have someone take a look at it to determin if the motor is bad.
Also if your playing a disc thay you recorded yourself, it needs to be finalized before other players can play the disc