My microwave computer seems to be possessed

E4 normally indicates a problem with either the keypad or a sensor. Since the oven is resetting, it may be the keypad or even the control circuit board. Below is my info on keypads, which may help, followed by more info: You may also have a bad keypad, which in many cases can be replaced. KEYPAD TROUBLE A bad keypad may be worn out due to age, damaged, or it may have gotten wet or otherwise contaminated. Moisture and contamination can be caused by not using the fan when boiling on the stove top (for over the range models), direct spraying of cleaners, by storing the microwave in an unheated garage or shed, or infestation. I warn my customers to never spray cleaner directly onto the microwave keypad, since the liquid can get inside and "lock up" or even ruin the keypad or controller. Apply an alcohol-based cleaner (such as the purple kind) to a cloth (since paper towels can scratch) and gently wipe it off. I suggest to my customers that they NEVER use any ammonia-based cleaner (like the blue stuff) on a microwave, since the ammonia will crack and distort polycarbonate plastics. DISCONNECTING AND CONNECTING THE KEYPAD 1. The keypad connection is the green or blue translucent plastic strip that plugs into a connector near the edge of the control circuit board. 3. There are two tiny tabs (one on each side) on the hood of the connector that you can gently pull up on to unlock the connector. Use equal and gentle fingertip force when pulling up. 4. The old keypad strip will lift out. 5. Put the new keypad strip in, making sure both sides are down fully. (If you are not installing a new keypad, clean yours with a pencil eraser or a soft cloth and alcohol.) 6. While holding the strip down, push the connector hood back down to lock it. -- If your keypad (membrane switch) is bad, you should be able to get one here: http://www.samsungparts.com/search/search.asp If you or a friend decide to work on it, we have *critical* safety, disassembly, and troubleshooting info at our site, which is linked at our listing here on FixYa: http://tinyurl.com/yzjozk If you still have questions, please post again.