HELP!!! What's wrong with my Samsung RS21 DCNS?

I have had this thing just under 3 years and since it came out of warrenty at just over 2 years I have had to defrost it countless times (not bad for a frost free freezer). The first thing I notice is that my beer is really cold, and then mt water dispenser had stopped working (later found out it had frozen). Within a week my food is off and although the fridge is showing 6 degrees and my freezer is showing -16, when I unplug it and then plug it back in it shows 12 degrees. If it wasn't so big and heavy it would of gone through the window by now! My wife is really on my back as she thinks because I can repair boilers I should be able to repair anything, But with this thing I'm stumped. Please help.