Default Huawei G510-0200 issue. Can't install new ROM.

I got huawei G510-0200 from friend to try to fix it. The phone is allready rooted and has installed a custom ROM(SlimKat 4.4) and TWRP recovery. But when the software is booted up, all the time i get the pop up message of applications crashing(play store, messenger, nova launcher etc) and i didn't run any application. So here's the real problem... When i access recovery and try the full wipe, factory reset or installing new rom, twrp reports that actions are successful but nothing happened. Nothing has changed. The phone was not reseted, data and applications are still there and same rom is still running. Someone told me that issue could be partitions.

Anyone had this problem, any ideas how to solve it?

Thanks in advance...

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