Default Huawei U8950D dead spot and slow processing/lag problems

Hi, I was browsing one day using "Google Chrome" on my Huawei U8950D then all of the sudden my phone just hanged, the screen won't respond and the lock button doesn't work, so I had to remove the battery to reboot the device. When I turned the phone back on I noticed sudden slowness of processing of applications and a huge bar of dead spot just happened to appear on my screen, I haven't dropped it or got it wet, it just happened.

My suspicions was the software side causing hardware problems on the phone. I don't know if I can repair the screen through software but what I want to know is how can I fix the "Lag" part of the device, the "slow processing".

To be honest I'm not that much familiar to mobile devices and android software but I would really appreciate any help coming from you guys who might have experience the same problems or maybe knowledge in getting me out of the this mess.

Edit: I also experience unresponsiveness of the screen and I always need to press to lock button to sorta "refresh" the screen so it would respond again.

Need Help badly. Thanks in advance