how will i fix my phone?It stopped installing symbian application, what should i do?

[Zee]

I am trying to install kaspersky mobile antivirus on my phone because i think it had a virus, but when i tried to install it through nokia installer it says 'phone doesn't support the file'. I have a nokia 5300, and other applications also are messed up, like the music player and it doesn't also recognize my headset. What should i do?pls help