Default [Q] Galaxy S2

I have galaxy s2 phone. It's korean version and model number is SHW M250S. I converted my phone to a international phone. Now phone has some problems.
1.Screen lock is working.
2.When I hold power button, power button menu is not displaying.
3.Application memory fill-up automatically. I install about 15 apps. But day by day , empty space of application memory is deceasing. Please help me to resolve this problems.