guitar noise question. please help.

[madguitar1086]

I have a gibson explorer that is brand new. I play heavy/speed/thrash metal. When i play distorted open powerchords (E5), and then abruptly stop the chord (with my right palm, and the fingers on my left hand) there is a short "eek" sound that the guitar produces. It would sound something like this: BOOOONG, eek. BOOONG, eek. It is very annoying. I discovered it today. I then plugged in my Epiphone Explorer...it does NOT do this. I plugged in my ESP explorer...it does NOT do this. Needless to say i hate gibson, considering this is my second gibson explorer. The first one had to be returned due to a warped fretboard. i have an ESP strat-style guitar that used to make this same sound, but it had a tremolo system, and the springs in the tremolo were causing the sound. So i padded them. The explorer does not have springs, nor a tremolo. What do i do? Please help.