My iPhone 4s is still not turning on, cut off completely?

So last night about 11pm, my iPhone 4s was charging, it was on 93%… I had a few apps open (not many) and had to quickly go on the browser whilst charging, next thing i know it switched off, just completely black.

I've tried resetting, holding both buttons for at least a minute,
i've checked the liquid indicator things
i have it connected on my laptop but it's also broke and hasn't been able to turn on in ages, but plugged it in to a different laptop with itunes and no luck.

i really don't know what to do?

if I take it to apple can they access my stuff even though its locked? Like if i sent it away

i don't have insurance

I'm stumped here, any chance you could tell me what buttons you held down to try and boot it back up? This happened with my iPhone 4s twice and plugging it into the computer and holding down the home and lock buttons to try a soft reset worked. Get back to this with me.