Alternatively, the GFCI plug is just a small scale breaker that could be worn out, especially if it took a big hit, like a malfunctioning microwave.If the GFCI doesn't reset when you press the reset button it's possible the fault still exists and is causing it to trip again. In that case it will be best to have an electrician look at it.
What are the reset and trip buttons? I noticed that there are two separate buttons in the middle. I suppose those are, but if true, which is which?