SE K810i 5-way navigation key problem

I recently got a used K810i, turned it on and found out that navi up and right are not working at the menu. It was also branded with Netcom (Norway) and the funniest part of all, when I turn on a game or the music player, the navi key works just fine. Furthermore, when I use up and right keys when the keyboard is locked, it asks me to unlock, in addition the key tones are also working when the keyboard is unlocked (which means the buttons are obviously not dead). I thought never mind that, I can always reflash the phone and it would be like brand new. The only problem is, that when I reflash it, the buttons still don't work, no matter what firmware I use, K810i or K800i, no response. That's why I need your help figuring out what's wrong with it. Any suggestions?


P.S. Pardon for my English.