What i am doing wrong ?

Hello,
I searched the forum for hours and hours, some of the things I was able to understand, but a lot I didn't.. Anyway, I have a problem now .. I tried to unlock the bootloader, I found the unlock code, did what had to be done in this tutorial - http://forum.xda-developers.com/xper...cking-t2332900 - but now when i turn on the phone - next happens: Sony logo pass, xperia logo pass and then loading waves are there forever and that's it.. can't boot .. ( am i wrong about boot? new about this so i am not sure if that is correct ).

Here is log when i tried to unlock bootloader:

Code:

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17/022/2015 12:22:06 - INFO  - Unlocking phone using key ********
17/022/2015 12:22:07 - INFO  - ...
17/022/2015 12:22:07 - INFO  - OKAY [  0.447s]
17/022/2015 12:22:07 - INFO  - finished. total time: 0.447s
17/022/2015 12:22:07 - INFO  - Device will reboot into system now
17/022/2015 12:22:07 - INFO  - Unlock code saved to C:\Users\***\.flashTool\registeredDevices\***\ulcode.txt
17/022/2015 12:22:07 - INFO  - Device disconnected

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So what i need to do now ? Flash it? ( i flashed once yesterday cuz i had the same problem with waves, also when rooted phone when i wanted to install fonts on the phone.. :( )
So, can i use some other software to flash it? By the default it's 4.2.2, can i download some other software like kitkat or lollipop ?

There are many things that i can't still understand but i am learning and sorry if i did mistake somewhere ( English is not my first language so i am trying to do best :) )