99 Alero factory amp

what happens if the system is working (i.e. you leave it at that barely audible volume), you turn the car off -park it or whatever, then go out to it the next day and turn it on, and immediately turn the volume up to about 40%....does it immediately shut off? Or does it take a few minutes before it will shut off?

It sort of sounds like one of the components is drawing too much power and blowing a fuse, but you never had to replace any fuses and you said eventually a few days later it would work.  That kind of behavior sounds more like the car has circuit breakers;  that would be a first for me though to see a factory installed circuit breaker for the radio's constant power wire.  Even then though it doesn't make sense that it takes 2 days to reset....

The whole thing is really odd...Seems like there is no rhyme or reason for when it decides to start working again. If i leave it barely audible it seems to stay on. (But I can't seem to leave my fingers off of it). It usually takes anywhere from a few seconds to min. before it shuts off. But, it shut off on me about 3 days ago and hasn't come back on since. My husband has checked everything he can..and since I can't stand not having music. I'm probably gonna take it to a stereo shop. Although, I was hoping not to.  I know it's hard to diagnose problems just from the information that I give you. But I really do appreciate all the input. Thanks again

Yea you're gonna need to have someone with a multimeter check the radio wires for voltage before, during, and after it cuts out.  And possibly new +12v constant (fused and run directly to positive battery terminal) and +12v switched (fused and run directly to brown wire in the ignition switch harness) wires will need to be run.

If u don't mind if you could let us know if/when you find out what the problem is, just for everyone's future knowledge

I'll be sure to let you know when it's figured out