Galaxy S5 Freezes Constantly I have a Samsung Galaxy S5 from Verizon, bought a little over one year ago. As soon as the one year warranty was over the device started acting up. Right now it is in an unreliable working state.

Symptoms:


The device freezes almost constantly at a rate of at least once an hour (4 times in the past 3 hours).  
There is not one app in particular to cause the freeze, that I can trace to. It seems that any time I do something which requires it to work a little, like loading a web page, brings the device to a freeze.  
Sometimes it just restarts. 
Sometimes it says "Start Up Failed" when booting up.


What I've done:


Removed the SD card completely.
Reset the device to factory defaults multiple times (about once per week). After this, it works good for a few days then goes back into freezing mode.
Uninstalled most of the apps, especially the once I don't really use daily.
Disabled all the pre-installed Verizon apps (the once that I could).
Disabled auto updates.
Took the device to the local Verizon shop and they didn't do anything to help, besides trying to get me to buy something else.


Any idea of what else I could do to fix this issue? 

EDIT

The device got to a point where it became impossible to perform any operations. If it wasn't constantly restarting, it would restart at the very first operation. Any attempt to do anything on the device sent it into restart.

I was able to talk to a few technicians from Samsung and they determined that the problem sits with the hardware, perhaps the motherboard. Therefore I ended up sending the device to Samsung for repair.
As a method of starting to debug this, Linux keeps a log for the kernel. I'm not sure if /proc/last_kmsg is there or not, but you want the kernel log.

I'd start by replacing the stock recovery with TWRP. Whether or not you want to Flash to a different rom. TWRP has a file browser. It should let you save the kernel's log either way. You want to pay attention to two files:


/var/log/boot.msg (useful in the state after the failed boot)
/var/log/syslog (useful in the state after the crash, and the state after the boot)


You'll want to thoroughly examine these files and paste the contents up here. It's possible the problem is hardware though. I'd flash CM13 (because it's all around better), and see if that fixes it. If problems persist on a fresh CM13, you know you've got a hardware issue.