I'm really hoping someone can help me out here. I'm no noob but I'm not that technically savy so bear with me pleas.

 

I have an internattional i9300. Bought unlocked from dick smith. Been running a nightly of CM mod 10 for the last few months. All going fine when right out of the blue it restarts and gets stuck in a boot loop. I boot into recovery (CWM) and clear cache and delvik cache. This time it gets past the boot screen and says 'Android is updating: Optimizing app 1 of 176'
It gets up to 11 and reboots... so still in a loop.

I found stock firmware (I9300XXALE8_I9300NZCALE5_I9300XXLE8_HOME.tar.md5) and flashed with odin. Then after a reboot it hangs on Samsung boot screen. I reboot to recovery and do factory reset.

 

This is where it gets really dark. Now it wont boot at all. Not even into recovery. I can get into Odin mode but where it onces said GT-i9300 next to Product name it now says nothing. Now when I try to flash anything with odin it comes up with an error about the PIT. (whatever that is)

 

I have absolutely no clue what I should try next. Obviously my warranty is gone out the window... and down the river.  Is there any hope? anything I can try that might fix it.