blue screen only after start up

after rebooting, the screen is grey and the little wheel spins. after that the blue screen appears and that is as far as it gets.

WHEN BOOTING UP THE SCREEN COMES ON AND THE SPINNING WHEEL. SOMETIMES THE SCREEN IS FUZZY. OTHER TIMES IT BOOTS ALL THE WAY UP TO THE BLUE SCREEN THEN THE IS LITTLE BLUE HORIZANTAL LINES AND IT GOES NO FURTHER, I'D SURE APPRECIATE SOME ASSISTANCE ON THIS. THANK YOU TERRY

SORRY SIR, I DO NOT HAVE THE ORIGINAL INSTALLATION DISC. THANK YOU FOR RESPONDING SIR PERHAPS THERE IS SOMETHING ELSE WE CAN TRY. I TRULY APPRECIATE YOUR TIME AND KNOWLEDGE. TERRY