Here's how to reset to factory defaults: http://www.samsung.com/us/support/SupportOwnersFAQPopup.do?faq_id=FAQ00001316&fm_seq=1484
Although I'll admit this sounds similar to what you've already done. So let me either way what the result is.
Light bulbs you shouldn't buy
There are plenty of dimmable LED light bulbs, but make sure you don't buy the ones that flicker when you dial them down.