Default [Q] [Please Help!] Huawei G300 booting problem (signature image verification failed)

Hi im new to the android world and im also new to this forum/website and im not too sure what to do or where to post so im sorry if im posting in the wrong section but i really badly need help!

I got the Huawei Ascend g300 off of my sister yesterday and she had sent it back to huawei via Vodafone (ireland) to get fixed because of numerous problems (Twice) .. she had just received it from vodafone (saying that there was a new motherboard and screen installed and that it was working perfectly.) she came home gave me the phone,
i turned it on and it worked fine for about 20 minutes.. then it froze and rebooted and again and again and hasnt stopped since.
Now its giving me a error screen saying signature image verification failed and also some error with my appboot/boot i really have no clue of what to do the phone is running android 4.0.. can someone please help me!?