can not start my laptop?

when i start up my laptop compaq700 message come window did not start successfully a recent hardware or software change might caused this - there 4 option 1 safe mode 2 safe mode with networking 3 safe mode with command prompt 4 last know good configuration and start window normally - i pick safe mode when window just about to start up my laptop reboot again and same message come window did not start up successfully i did not install any software since last year please help

david
September 2009