Default [Q] Restore original bootloader


I was trying to root my phone (Samsung Galaxy Star Pro) following the method on this thread:
I flashed the recovery file, and also the bootloader file attached there. I successfully rooted the phone, but now when I restart it, all I get is a white screen. Please help me. I tried everything. I don't think I can download the complete ROM for my phone which is around 500 MB because the Internet connection over here is slow as hell. Please help someone. PLEASE.