suddenly no start 95 astro

I noticed today when i turned off the ignition in my 95 RWD astro (4.3 vortec) that there was a peculiar noise in the dash somewhere like a buzzer that did not buzz too good. I carried on and went on with my day.Later i drove it around and returned home. I turned the van off again and the noise reappeared but this time, there is really no power, but there is. i wiggled the key and the clock would flash on on the radio. every time i try the key, the only response is a stuypid funny sounding buzz that is not my regular buzzer . interior lights do not light up. power accessories do not work. but that dang clock lights up once in a while consistantly when i play witht he ignition. there is another buzzing sound at that time coming from the dash on the passenger side. This is very disturbing. Just super glad that i made it home again. this astro is a beauty but it has it's bugs and gremlins. i think it is prolly the battery, but im no mechanic . and also this is my 1st post here and i am thrilled and anxious to see how it goes. I am really no car entusiaste, just someone that wants to fix his car so i can get back to work on the boat! Haha! Help!!!!

dosent sound like a battery problem, i can try and find out what may be wrong, il get back to you