Iphone Won't Power On

[krawfo]

I just bought a used Verizon IPhone 4S 2 days ago and everything was working fine after performing a reset and transferring contacts. Today it went into sleep mode with 35% battery remaining. An hour later I pressed the home button and nothing happened. Then I tried the hold button and nothing. I plugged in the charger cord - nothing. I connected the USB cable to my computer - nothing.
As a last resort I pressed and held the hold and home buttons at the same time. The phone powered up (Apple logo) and everything was fine. The same thing happened a day later.
I got up this morning and noticed the clock was 30 minutes slow. I went into SETTINGS to make sure Date & Time were set to AUTOMATIC. I happened to notice that WIFI was off and I was unable to swipe the button to on. I powered off and then on again. Now the time was correct and WIFI was on.
BTW, I'm running IOS 6.1.3

It has been suggested that I download the full ipsw and use that to restore the phone. A good idea???

Any ideas on what happened?
Is this a sign of an impending failure?
Thanks for your help.
iPhone 4S, iOS 6.1.3

 

[Darkstar2007]

Yes, a factory restore would be beneficial.

If that doesn't work, it's a hardware issue unfortunately. Check to see if its still under warranty with apple. You might be in luck?

 

[krawfo]

Check to see if its still under warranty with apple.

I already checked warranty status - no joy

I noticed many web sites with links to ipsw files. How do I know which ones are legit?

Thanks for the reply.

 

[Mickey330]

If I may be so bold: we have a thread in the Hacking sub-forum that has all the IPSWs. The link is here: http://www.iphoneforums.net/forum/i...ple-ios-firmware-download-links-iphone-17213/

It's kept up-to-date and, IMNSHO, it's fully reliable.

Marilyn