Hello and Welcome to FixYa!
You have to update / reprogram the phone's firmware, it is easy for an End User, all you need is the USB Data cable of your phone, if you have it then proceed, if you didn't have one then do note, there is no code or something similar to format the SE phone, don't get fooled by anyone. I've done is many times, so I'm telling you on the behalf of my experience. This is a famous issue with SE phones called WSOD (White screen of death).
Ok now if you got the cable, download the Update utility from the link I've provided below, all you have to do is to download the utility, install it and run the application, it will automatically check for updates and then the wizard will guide you accordingly on how and when to connect the phone. Its easy and I'm 99% sure this will resolve your problem, the 1% is reserved in case there is some hardware issue.
If you are having any questions/issues do ask me. I'm here to help.
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P.S: Sony Ericsson K610i update utility