Samsung SGH-i550w Messed Up!

[gkn]

Hi everybody, this is my first post and i need your help deeply.

I have been using Samsung SGH-i550w for about almost five years (and love it).
Symbian S60v3.

I have never hacked my phone.
It also has first firmware, that have come in it.

My problem is the following. I was trying to install some .jar & .sis file like x-plore, killer mobile, dictionary, etc...

Some programs worked well the others gave errors, then I have uninstalled the unnecesseary apps that I installed previously .

Then things got worse...

Firstly i cannot get response from pushing the yes button, the screen flashed and refused to open. I have tried many time but the result was same. :( I have restrated many time, with/without memory card. But still no response.

Today, while trying to send an sms, it happened again. When I tried to open messages screen flashed (open and close within microseconds) and could not open my messages.

When i restarted my phone, it said:

App. closed Data Connection Logger (and it keeps saying every restart)

I can not understand what the problem is. My phone was working well till today. What can solve this problem?

Please help Thanks in advance


Note:Sorry for my poor English.