PC CRASHES WHILE ON LINE

WHILE I’M ON LINE SOMETIMES I LOSE MY POINTER, AND EVERYTHING ELSE. I’M NOT SURE IF THIS IS A HARDWARE OR SOFTWARE PROBLEM. I SCAN MY HARD DISK FOR ERRORS ALMOST EVERY TIME I’M FINISHED ON LINE. IBM APTIVA,133Mh, PENT.PROSSER, 48MIGS RAM, 1.99GIGHARD DRIVE, WIN.98, MICROSOFT INT.EXPLORER5.0. IF I HAVENT GIVEN ENOUGH INFO PLEASE CONTACT ME. THANKS