What should i do to my ibm pentium 4?..it shutdown while i'm using it.. then,when it restarts nothing happened?

while i am using facebook, my computer turned off.. the when i restart it.. there was an error.. time error and system configuration error... i fix the time error... and i checked the boot menu, the videocard the should be agp... and then i restart again .. error again?... i replace the cmos batterry, and again nothing changed.... what should i do?.. hmmmm i think the one that will going to help me was a genius,, and cute ^_^ hehehe.. please help me...tsk.. thanks a lot! many many thanks!