Program error in nokia 6600

When I boot the phone (Nokia 6600), as soon as the nokia logo comes up it gives a beep sound and displays KL START application with the option of choosing only ok,when u click ok, the phones boots normally. After this the bluetooth refuses to open, calendar refuses to open and the file manager refuses to open.When the phone is left on, an error message occurs at intervals and this error message says "error loading Screen saver". On some occasions the bluetooth loads then starts to malfunction, I have scanned the phone wit various anti-virus software but the proble still persist. I seriouly suspect the Operating System of the phone is it possible? and if so can I install a new OPS?