Thank you michaaa62,

Actually, It hadn't recognized the Memory Card once because of the magnet. After that, It worked when I inserted the other magnet into the back cover.

But all of the certain, it did it again. Don't have any clue.

I don't think it's the hardware. To be honest, I am keen to do the factory reset but I am a little confused of how to do it right and I don't have much time at the minute for reinstalling and configuring all the software again as the phone is running great for now.

thanks dude

SlashN900