I have had this dryer about 4 years brand new and I just took dry clothes out and put another load in and it would not start. The lights come on but nothing happens. This is crazy and an inconvenience because I have things that need to be dried.
If you have verified that the child lock is not engaged, this will need to be addressed by having the unit serviced. You can find a local service center at this link: http://www.samsung.com/us/support/service/location. If you purchased an extended warranty for the dryer through your retailer, you would need to contact them to set up the service.