Why won't my dryer tumble?
Another thing that could be wrong would be that the drive belt had snapped. They do wear out. Replacements exist. How hard they are to install varies from model to model; mine wasn't bad, but did require disassembling the drier to the point where I could lift out the drum, and then required some access from the back to get the belt hooked around the drive pulleys properly. (I'm sure a pro could have done it entirely from the front, but this is the approach the maintenance manual I found online recommended.).

I'd suggest looking for the repair manual first. That'll generally have some problem analysis tips, and you'll want to see where the part is located and how to replace it before you decide to do it yourself.

Reminder: Disconnect from the wall before servicing!