Found this Samsung model problem in the Welbilt section but will try to help just the same. Hope you find it.
The first thing to try is a "hard reset". Unplug it from the power line for a few minutes, plug it back in, set the clock, then try again.
You can download your owner's manual here:
http://downloadcenter.samsung.com/content/UM/200303/20030324114252562_DE68_00064C-02.pdf
I always recommend that users spray the cleaner on a soft cloth (not on the keypad itself) then wipe the control panel off.
Also, I always recommend non-ammonia cleaners since ammonia can crack and damage plastic.
Otherwise, the spray can get into the controls and lock it up or make it act odd.
If it does not dry out over time, it may need to be manually dried or blown out.
The keypad may be damaged or worn out, or control unit may be damaged.
You can order a new keypad (membrane switch) here:
http://www.samsungparts.com/search/search.asp
Please write back with more details if you need further help.
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