Main functions failure (USB Storage, WIFI, SIM, Camera) after boot in Samsung Galaxy Mini 2 running Android 2.3.6 PROBLEM

So far, I noticed that after I turn it on and it completely loads up, it can't:  


show notification-bar  
use camera  
detect or recognize "internal USB storage"  
detect or recognize "SD card"  
use WIFI (when clicked, just says "Error")  
sometimes use cellular network (have good signal strength but can't reach the network)  
sometimes detect "SIM card" (PIN asked on booting but on settings page can't detect!)  




WHAT HAPPENED

My device is pretty heavy on apps (about 200 apps installed), sometimes while I`m working, it hangs and everything just freezes but after about half hour cellular network automatically forced to turned off and everything will be just normal and after reset, net will be back too but the last time that this happened, it took about two hours and when I reset the device, my problems began.  



WHY  

I think  all of this is happening because of two reasons:  


the Operating System kernel drivers maybe damaged  
hardware failure (maybe some IC controller fried!)  
because device can't detect internal/external storage so many apps (such as operating system's own apps) can't work properly  




DEVICE INFO  


Model number - Samsung Galaxy Mini 2 (GT-S6500D)  
Android version - 2.3.6  
Baseband version - S6500DJPLI1  
Kernel version - 2.6.38.6-1206137  
Build number - Gingerbread.JPLJ1  
Status - Rooted  




P.S.  

I know that I simply can use Android's Recovery mode or Odin for flashing a new Operating System but I don`t want to wipe all of my data (very important to me!)
200 apps on Gingerbread :O, time to upgrade now. Even on my OnePlus One with 3gigs RAM and 64gigs Internal Storage, I merely have 20-30 downloaded apps with 2-3 in start-up.

But anyhow, follow this:


Format and install some custom ROM like Cyanogenmod
Keep only required apps.
Remove apps from start-up. Use AIO Toolbox from Play Store.
Use AIO Toolbox on regular basis to clean up.


For all your apps backup: I believe in that list of 200 apps, you must have some system tools. Check if it has backup option for apps or not. Even you can create backup from recovery mode too, if your recovery supports. TWRP/Cyanogenmod/ClockWorkMod do have this option.